SSC JE (ME) Mock Test - 3


200 Questions MCQ Test Mock Test Series for SSC JE Mechanical Engineering | SSC JE (ME) Mock Test - 3


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Attempt SSC JE (ME) Mock Test - 3 | 200 questions in 120 minutes | Mock test for SSC preparation | Free important questions MCQ to study Mock Test Series for SSC JE Mechanical Engineering for SSC Exam | Download free PDF with solutions
QUESTION: 1

Select the number which can be placed at the sign of the question mark (?) from the given alternatives.

Solution: The pattern follows here is,

Working on column

28 –24 = 4; 42 = 16

40 – 32 = 8; 82 = 64

Similarly,

36 – 28 = 8; 82 = 64

Hence, option 64 is the correct answer.

QUESTION: 2

Select the related number from the given alternatives.

434: 25:: 328:?

Solution: The pattern followed here is,

(Add even numbers – Add odd numbers)2

(4 + 4 - 3)2 = 25

Similarly,

(8 + 2 - 3)2 = 49

Hence, option 49 is the correct answer.

QUESTION: 3

In the following question, the symbols ×, ÷, and + are used with the following meaning as illustrated below:

J + K means ‘J’ is the wife of ‘K,’

J × K means ‘J’ is the mother of ‘K.’

J ÷ K means ‘K’ is the sister of ‘J.’

If N + M÷P × Q, how is N related to Q?

Solution:

Hence Aunt will be the correct answer.

QUESTION: 4

From the given answer figures, select the one in which the question figure is hidden/embedded. (Rotation is not allowed)

Solution: Out of all the four figures, the following figure is only present in

Hence option 4 is the correct answer.

QUESTION: 5

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.

VSU, WTV, XUW,?

Solution: The Pattern is as follows,

Hence, option YVX is the correct answer.

QUESTION: 6

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.

THR, UFS, VDT, ?

Solution:

Hence, option WBU is the correct answer.

QUESTION: 7

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.

X, M, T, O, R, ?

Solution: Solution: The pattern is as follows,

Consecutive prime numbers are subtracted and added.

Hence, option P is the correct answer.

QUESTION: 8

Select the odd word from the given alternatives.

Solution: All except Android are internet browsers. Android is an operating system.

Hence ‘Android’ is the correct answer.

QUESTION: 9

Seven persons are seating around a circular table facing the centre. All persons are Asif, Bucky, Chirag, Dev, Esha, Farida, Gautam. Bucky is an immediate neighbour of Gautam and Farida. Dev is not an immediate neighbour of Chirag. Chirag sits second to the left of Gautam. Asif is an immediate neighbour of Chirag but not of Gautam.

Who sits second to the left of dev.?

Solution: 1. Bucky is an immediate neighbour of Gautam and Farida, and Chirag sits second to the left of Gautam.

2. Dev is not an immediate neighbour of Chirag Asif is an immediate neighbour of Chirag but not of Gautam

Bucky will sit second to the left of Dev

Hence Bucky has the correct answer.

QUESTION: 10

Select the option in which the numbers share the same relationship as that shared by the given set of numbers.

56, 64, 72, 80

Solution: The pattern follows here is, the given series is in the ratio of 7: 8: 9: 10

Similarly,

Series 91, 104, 117, 130 will be in the ratio of 7: 8 : 9: 10

Hence 91, 104, 117, 130 is the correct answer.

QUESTION: 11

Select the correct mirror image of the given combination when the mirror is placed on the right side of it

Solution:

We can see that the pictures are perfectly mirrored here.

Hence option 1 is the correct answer.

QUESTION: 12

Select the related word from the given alternatives.

SAMSUNG: SOUTH KOREA:: MICROSOFT:?

Solution: The logic here is,

Samsung is from South Korea.

Similarly,

Microsoft is a company from the United States.

Hence ‘United States’ is the correct answer.

QUESTION: 13

Select the pair of odd numbers from the given alternatives.

Solution: The pattern follows here is,

To get the second number, add all the digits of the first number and then divide by 2.

5 + 8 + 3 = 16; 16 ÷ 2 = 8

2 + 6 + 6 = 14; 14 ÷ 2 = 7

6 + 6 + 8 = 20; 20 ÷ 2 = 10

9 + 2 + 7 = 18; 18 ÷ 2 = 9

Hence option 927 : 11 is odd among all four.

QUESTION: 14

Arrange the given words in the sequence in which they occur in the dictionary.

1. INSINUATE

2. INSIDIOUS

3. INSIPID

4. INSATIABLE

Solution:

INSATIABLE

INSIDIOUS

INSINUATE

INSIPID

Hence 4213 is the correct answer.

QUESTION: 15

Identify the diagram that best represents the relationship among classes given below

Gas, Oxygen, Aluminium

Solution: Oxygen is a gas, and aluminium is a metal, so that it will be a separate subject.

The above-shown diagram expresses the best relation between gas, oxygen, and aluminium.

Hence, option 4 is the correct answer.

QUESTION: 16

Identify the diagram that best represents the relationship among classes given below

Currency, Qatar, Doller

Solution: Qatar is a gulf country, and Doller is a currency,

The above shown diagram expresses the best relation between Qatar, Currency, and Doller.

Hence, option 3 is the correct answer.

QUESTION: 17

Select the related number from the given alternatives.

WATCH: TIME:: CALENDAR:?

Solution: The logic here is,

Watch is used o see ‘Time’

Similarly,

Calendar is used to see ‘Date’

Hence ‘DATE’ is the correct answer.

QUESTION: 18

Select the related number from the given alternatives.

878: 448:: 638:?

Solution: The pattern here is, multiply the digits of first number = second number;

8 × 7 × 8 = 448

Similarly,

6 × 3 × 8 = 144

Therefore 144 is the correct answer.

QUESTION: 19

Select the related number from the given alternatives.

ZERO: AARYABHATT :: TELEPHONE:?

Solution: The logic here is,

Zero was invented by Aryabhata

Similarly, Telephone was invented by Graham bell

Hence ‘GRAHAM BELL’ is the correct answer.

QUESTION: 20

In a certain code language, "GREAT" is written as "2015187," and "BURSH" is written as "81918212". How is "DREAD" written in that code language?

Solution:

Similarly,

Hence, option 415184 will be the correct answer.

QUESTION: 21

In a family of six members, namely J, K, L, M, N, O. J who is the grandfather of O is Father of L. M is the mother of K who is the sister in law of N. O is the son of N who is the husband of L. There are two couples in this family.

How is L related to K?

Solution:

Hence sister is correct answer

QUESTION: 22

In the following figure, the square represents boys, the triangle represents cricketer, the circle represents biker. Which set of letters represents boys who are bikers?

Solution: Out of total 62 boys,

Only boys who are biker:

25 + 9 = 34

Hence option 34 is the correct answer.

QUESTION: 23

Which one of the given responses would be a meaningful order of the following?

1. Classification

2. New product

3. Collection

4. Recycle

5. Waste

Solution: Here the pattern will be,

It is a waste recycle process, starting from ‘Waste’ dumped by us, it is ‘Collected.’ After collection of various types of waste will be ‘Classified’ into different categories. Finally, it is ‘Recycled’ and ready to make a ‘new product.’

Hence option 5, 3, 1, 4, 2 is the correct answer.

QUESTION: 24

In a certain code language, "LONE" is written as "OPMD," and "MIND" is written as "OJNC.” How is "SIGN" written in that code language?

Solution: The pattern follows here is,

Similarly,

Hence the option HJTM is the correct answer.

QUESTION: 25

Study the following information carefully and answer the questions based on it.

Some friends are seated in a row facing north. X, who is the only neighbour of Q, sits third to the left of P. Friends sit right to P is two less than friends sit left to P.

How many seating positions are in this row?

Solution: The seating will be as follow

Hence, there are a total of 7 friends in this row.

QUESTION: 26

Select the related word from the given alternatives.

GKPT: VRMI:: BJNO:?

Solution: above-shown

Similarly,

Hence QPLD is the correct answer.

QUESTION: 27

Select the related word from the given alternatives.

Nitin Gadkari : Nagpur :: Smriti Irani : ?

Solution: The logic that follows here is

Nitin Gadkari’s constituency is Nagpur

Similarly,

Smriti Irani’s constituency is Amethi

Hence Amethi is the correct answer.

QUESTION: 28

If 5 θ 9 ∂ 3 = 30 and 5 θ 6 ∂ 2 = 20, then 6 θ 8 ∂ 2 =

Solution: Logic: A θ B ∂ C = A × (B – C)

5 θ 9 ∂ 3 = 15 → 5 × (9 – 3) = 5 × 6 = 30

5 θ 6 ∂ 2 = 15 → 5 × (6 – 2) = 5 × 4 = 20

Now,

6 θ 8 ∂ 2 = ? → 6 × (8 – 2) = 6 × 6 = 36

Hence, 36 is the answer.

QUESTION: 29

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.

18, 21, 30, 57, 138, ?

Solution: The pattern followed here is,

Prime numbers starting from 3 are added,

18 + 3 = 21;

21 + 9 = 30;

30 + 27 = 57;

57 + 81 = 138;

138 + 243 = 381

Hence option 381 is the correct answer.

QUESTION: 30

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.

75, 69, 81, 63, 87, ?

Solution: The pattern followed here is,

75 - 6 = 69

69 + 12 = 81

81 - 18 = 63

63 + 24 = 87

87 - 30 = 57

Hence option 57 is the correct answer.

QUESTION: 31

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.

28, 14, 14, 21, 42, ?

Solution: The pattern followed here is,

28 × .5 = 14

14 × 1 = 14

14 × 1.5 = 21

21 × 2 = 42

42 × 2.5 = 105

Hence option 105 is the correct answer.

QUESTION: 32

In the following question below, some statements are given, followed by some conclusions. Taking the given statements to be true even if they seem to be at variance from commonly known facts, read all the conclusions, and then decide which of the given conclusions logically follows the given statements.

Statements:

All peas are berry

Some berry are chips

Some chips are flavoured

Conclusion:

I. some berries are not flavoured.

II. All peas can be chips.

Solution: The least possible Venn diagrams as follows

I. some berry is not flavoured → False (as we cannot conclude a negative from positive statements)

II.All peas can be chips → True (it is possible that all peas can be chips)

Hence, only conclusion II follows.

QUESTION: 33

Select the correct mirror image of the given combination when the mirror is placed to the right side of it.

Solution:

We can see that the pictures are perfectly mirrored here.

Hence option 1 is the correct answer.

QUESTION: 34

Karan’s brother's age is three times his age; after the 5-year ratio between the age of Karan and his brother will be 1: 2. What will be the age of Karan’s father, who is 25 years older than him?

Solution: Let consider the age of Karan = x;

Then the age of Karan’s brother will be = 3x;

After 5 year

(X + 5)2 = 1(3X + 5)

2X + 10 = 3X + 5,

X = 5

So Karan’s father age will be = 5 + 25 = 30

Hence option 30 is the correct answer.

QUESTION: 35

In the following question below, some statements are given, followed by some conclusions. Taking the given statements to be true even if they seem to be at variance from commonly known facts, read all the conclusions, and then decide which of the given conclusions logically follows the given statements.

Statements:

Some winners are gold

Some silver is winner

No gold is silver

Conclusion:

I. some winners are not silver.

II. some winners are not gold.

Solution: The least possible Venn diagram is as follows

some winner is not silver → True (Winners which are Gold will never be Silver)

some winner is not gold.→ True (Winners which are Silver will never be Gold)

Hence, both conclusions follow

QUESTION: 36

If ‘@’ means ‘÷,’ ‘%’ means ‘ ×,’ ‘$’ means ‘ - ’ and ‘#’ means ‘ + ’ then what is the value of

78 @ 6 # 13 $ 8 % 3

Solution:

After applying all the operators on their respective symbol place, we get

78 ÷ 6 + 13 – 8 × 3 = 2

Hence 2 is the correct answer.

QUESTION: 37

If the following words are arranged in the sequence as they appear in the dictionary, then what will be the sequence as per the dictionary order?

1. PRECLUDE

2. PREROGATIVE

3. PRECIPITOUS

4. PRECIPITATE

5. PRECURSOR

Solution: The dictionary order will be as follow,

PRECIPITATE

PRECIPITOUS

PRECLUDE

PRECURSOR

PREROGATIVE

Hence option ‘4, 3, 1, 5, 2’ is the correct answer.

QUESTION: 38

From the given answer figures, select the one in which the question figure is hidden/embedded.

Solution: Out of all the four figures the following figure is only present in 3

Hence option 3 is the correct answer.

QUESTION: 39

Select the pair of odd words from the given alternatives.

Solution: The logic here is that all except Nepal: Bhutan are a pair of countries and their respective capital.

Hence ‘Nepal: Bhutan’ will be the odd word.

QUESTION: 40

If “TARKASH” is coded as “78” and “OPPOSE” is coded as “86,” then how will “STATION” be coded as?

Solution: The pattern is as followed,

Add the place value of alphabets, T = 20; A = 1; R = 18; K = 11; A = 1; S = 19; H = 8,

after adding the obtained value we get

20 + 1 + 18 + 11 + 1 + 19 + 8 = 78

Similarly, O = 15; P = 16; P = 16; O = 15; S = 19; E = 5,

after adding the obtained values we get

15 + 16 + 16 + 15 + 19 + 5 = 86

Thus, the logic for STATION will be,

S = 19; T = 20; A = 1; T = 20; I = 9; O = 15; N = 14

after adding the obtained values, we get

19 + 20 + 1 + 20 + 9 + 15 + 14 = 98

Hence option 98 will be the correct answer.

QUESTION: 41

Select the correct alternative to indicate the arrangement of the following in a logical and meaningful order.

1. Dig

2. Tree

3. Sapling

4. Fruit

5. Flowers

Solution: Here the sequence will be,

first ‘dig’ a hole and then plant a ‘sapling,’ after that it will become a ‘Tree’ and in seasons it will ‘Flowered,’ and finally, it will give ‘Fruits.’

Hence, option 13254 is the correct answer.

QUESTION: 42

Two different positions of the same dice are shown. Select the number that will be on the face opposite to the one having 3.

Solution: After observing dice, A, 5, and 4 is not opposite to 3

And through dice B, we can conclude that 6 and 2 is not opposite to 3

Hence, the remaining number 1 will be the opposite of 3.

Hence, 1 will be opposite to 3

QUESTION: 43

‘Song’ is related to ‘Lyrics’ in the same way as ‘movie’ is related to ‘________.’

Solution: Words/line of a song called ‘Lyrics’ in the same way all written data of a movie is called ‘Script.’

Hence Script will be the correct answer.

QUESTION: 44

Select the number which can be placed at the sign of the question mark (?) from the given alternatives.

Solution:

The pattern followed here is,

Working on column

Column1: 22 + 33 = 31,

Column2: 42 + 53 = 141,

Similarly,

Column3: 62 + 73 = 379

Hence option 379 is the correct answer.

QUESTION: 45

Study the following information carefully and answer the question based on it.

Suraj wants to go to school, so he starts from his house, and after walking 2 km straight, he reaches point A. From point A, he takes a right turn and walks for 200 meters, and then he turns again right and walks for 3 km to reach point B. From point B, he turns left and walks for 2 km. Finally, he reaches his school and faces south.

Suraj’s house is in which direction of his school?

Solution:

From the above illustration, Suraj’s house will be in North East of his school.

Hence North - East is the correct answer

QUESTION: 46

A piece of paper is folded and cut as shown in the question figures. From the given answer figures, indicate how it will appear when opened?

Solution: The paper will appear as follows when opened

Hence option 2 is the correct answer.

QUESTION: 47

In a certain code language, "TRAIN" is written as "OJBSU," and "TEJAS" is written as "TBKFU.” How is "MAJOR" written in that code language?

Solution: The pattern is as follows,

Similarly,

Hence option SPKBN will be the correct answer.

QUESTION: 48

In the following question below, some statements are given, followed by some conclusions. Taking the given statements to be true even if they seem to be at variance from commonly known facts, read all the conclusions, and then decide which of the given conclusions logically follows the given statements.

Statements:

All led are light

No light is dark

All dark is black

Conclusion:

I. Some black are led is a possibility.

II. some leads are dark.

Solution:

Some black are led is a possibility → True (It is possible that some black are led)

some led are dark → False (There is no direct relation between led and dark)

Hence, the only conclusion I follow.

QUESTION: 49

In the following question below, some statements are given, followed by some conclusions. Taking the given statements to be true even if they seem to be at variance from commonly known facts, read all the conclusions, and then decide which of the given conclusions logically follows the given statements.

Statements:

All dashboard is keyboard

All keyboard is mouse

No mouse is printer

Conclusion:

I. All dashboard is mouse

II. some keyboard are printer is a possibility

Solution:

All dashboard is mouse → True (Because all keyboard is mouse hence all dashboard will also be mouse)

some keyboard is printer is a possibility → False (because no mouse can be printer)

Hence the only conclusion I follow.

QUESTION: 50

Which two signs should be interchanged to make the given equation correct?

12 ÷ 6 × 2 + 18 - 8 = 46

Solution: After interchanging the operators,

1. 12 ÷ 6 × 2 –18 + 8 = - 6 ≠ 36

2. 12 ÷ 6 – 2 + 18 × 8 = 144 ≠ 36

3. 12 × 6 ÷ 2 + 18 – 8 = 46

4. 12 + 6 × 2 ÷ 18 – 8 = 4.66 ≠ 36

Hence option 3 is the correct answer.

QUESTION: 51

The Constituent Assembly of India was constituted on the scheme of –

Solution: The United Kingdom Cabinet Mission of 1946 came to India aimed to discuss the transfer of power from the British government to the Indian leadership, with the aim of preserving India’s unity and granting it independence. Formulated at the initiative of Clement Attlee, the Prime Minister of the United Kingdom, the mission had Lord Pethick-Lawrence, the Secretary of State for India, Sir Stafford Cripps, President of the Board of Trade, and A. V. Alexander, the First Lord of the Admiralty.
QUESTION: 52

The second Battle of Panipat was fought between

Solution: The Second Battle of Panipat was fought on November 5, 1556, between the forces of Bahubali, the Hindu general and Chief Minister of Aastha gargi, and the army of the Mughal emperor, Akbar.
QUESTION: 53

“Sarfaroshi Ki Tamanna Ab Hamare Dil Mein Hai” popular freedom struggle song during the British Raj period in India.

Solution: Sarfaroshi ki Tamanna is a patriotic poem written in Urdu by Bismil Azimabadi of Patna in 1921. It was also immortalised by Ram Prasad Bismil as a freedom war cry during the British Raj period in India.
QUESTION: 54

Who founded the Home Rule League in Madras in 1916 A.D.?

Solution: Tilak founded the first home rule league at the Bombay provincial congress at Belgaum in April 1916. Then after this, Annie Besant founded a second league at Adyar Madras in September 1916. Despite the banner of All India Home Rule League, there were two leagues, one by Tilak that worked in Bombay Presidency, Carnatic, Central provinces, and Berar. The Annie Besant’s league worked for the rest of India.
QUESTION: 55

The rate of tax increase as the amount of the tax base increases is called?

Solution: The rate of tax increase as the amount of the tax base increases is called Progressive tax.
QUESTION: 56

The guerilla warfare was pioneered by

Solution: Shivaji Bhonsle was an Indian warrior king and a member of the Bhonsle Maratha clan. Shivaji carved out an enclave from the declining Adilshahi sultanate of Bijapur that formed the genesis of the Maratha Empire.
QUESTION: 57

Who spoke: “At the stroke of midnight, when the world sleeps, India awakes to life and freedom”?

Solution: On the midnight of August 15, 1947, India’s first prime minister Pandit Jawaharlal Nehru addressed the nation with powerful lines, “At the stroke of the midnight hour, when the world sleeps, India will awake to life and freedom.” In the speech “Tryst with destiny,” which was delivered in Parliament, Nehru laid the roadmap for the future and highlighted the pain people have endured for long to get freedom.
QUESTION: 58

The item ‘Education’ belongs to the—

Solution: The Constitution of India provides a division of powers between the Union (Centre) and states. It divides all the subjects into 3 lists – The Union List (97 Subjects), State List (66 Subjects), and Concurrent List (47 Subjects); the Union List describes the subjects under the control of Centre Government, the State List describes the subjects under the jurisdiction of states being the Concurrent List describes the subjects which are under the joint jurisdiction of the Centre of States. The subjects which do not fall in these lists, i.e., residuary subjects, have been given to the Centre.
QUESTION: 59

Which one of the following Articles of the Constitution of India has provision for the President to proclaim national emergency?

Solution: Under Article 352 of the Indian Constitution, the President can declare such an emergency only on the basis of a written request by the cabinet of ministers headed by the Prime Minister. The Parliament must approve such a proclamation with a two-thirds majority within one month. Such an emergency can be imposed for six months. It can be extended by six months by repeated parliamentary approval-there is no maximum duration.
QUESTION: 60

Which Fundamental Right in the Indian Constitution states that every person has the right to practice, profess and propagate the religion of their choice.

Solution: Article 25 guarantees freedom of conscience and free profession, practice, and propagation of religion according to their choice.
QUESTION: 61

Which of the following was not a member of the drafting committee of the constitution-

Solution: The Drafting Committee had seven members: Alladi Krishnaswami Ayyar, N. Gopalaswami; B.R. Ambedkar, K.M Munshi, Mohammad Saadulla, B.L. Mitter, and D.P. Khaitan. At its first meeting on 30th August 1947, the Drafting Committee elected B.R Ambedkar as its Chairman. It was this committee that was entrusted with the task of preparing a draft of the new constitution.
QUESTION: 62

Which place is said to be the Manchester of South India?

Solution: Coimbatore is referred to as the “Manchester of South India” due to its cotton production and textile industries.
QUESTION: 63

How many Fundamental Duties are in the Indian Constitution?

Solution: Part IVA (Article 51A) of the Indian Constitution deals with Fundamental Duties. Originally, the Constitution of India did not contain these duties. Fundamental duties were added by 42nd, and 86th Constitutional Amendment acts. As of now, there are 11 Fundamental duties. The Constitution morally obligates citizens to perform these duties. However, like the Directive Principles, these are non-justifiable, without any legal sanction in case of their violation or non-compliance.
QUESTION: 64

Which town/city in India has got a tower (minaar) named after Muhammad Ali Jinnah?

Solution: Jinnah Tower is a landmark monument in the city of Guntur in Andhra Pradesh. It is named after the father of Pakistan, Muhammad Ali Jinnah, and is located on Mahatma Gandhi Road of the city as a symbol of peace and harmony.
QUESTION: 65

Fundamental Rights of Indian constitution have been adopted from which of the following nation-

Solution: The six fundamental rights recognised by the Indian constitution are the right to equality, right to freedom, right against exploitation, right to freedom of religion, cultural and educational rights, right to constitutional remedies.
QUESTION: 66

From the following languages given below, pick out of the one which is the official language of Maharashtra—

Solution: Marathi is the official language of Maharashtra and co-official language in the union territories of Daman and Diu and Dadra and Nagar Haveli.
QUESTION: 67

Who administers the oath of the President of India?

Solution: According to Article 60(Oath or affirmation by President), the Chief Justice of India administers the oath of the President of India.
QUESTION: 68

What is the minimum age required to become vice-president of India?

Solution: The minimum age required to become Vice-President is 35 years, according to Article 66(3)(b) of the Indian Constitution.
QUESTION: 69

During the colonial period, British capital was mainly invested in:

Solution: During the British Raj(from 1858 to 1947), the Indian economy essentially remained stagnant, growing at the same rate (1.2%) as the population. India experienced deindustrialization during this period. After 1857, the inflow of British capital and enterprise into India rose to an appreciable extent. The bulk of the imperialist capital was mainly invested in the externally oriented sectors like plantations, jute, and coal, and the trading and banking infrastructure established to service this sector. This ultimately led to the perpetuation of the subordination of Indian capital to the British capital with the ulterior motive of feeding Britain and other countries with cheap raw materials and food.
QUESTION: 70

Humayun Nama was written by

Solution: The Humayunnama was written by Gulbadan Begum (half-sister of Humayun).
QUESTION: 71

Investment that is dependent on the level of income or on the rate of interest is called –

Solution: Investment that is dependent on the level of income or on the rate of interest is called induced investment.
QUESTION: 72

Even after sunset, the air near the Earth’s surface continue to receive heat due to:

Solution: Even after sunset, the air near the Earth’s surface continues to receive heat due to Terrestrial Radiation.
QUESTION: 73

The Ahmedabad Satyagraha of Gandhi was directed against

Solution: Ahmedabad Mill Strike, 1918 was one of the initial movements led by Gandhi at the beginning of the 20th century after his return from South Africa. In February March 1918, there was a conflict between the Gujarat Mill owners and workers on the question of the Plague Bonus of 1917. The Mill Owners wanted to withdraw the bonus while the workers demanded a 50% wage hike. The Mill Owners were willing to give only a 20% wage hike.
QUESTION: 74

Which State Government had abolished “agriculture income tax” on plantation companies.

Solution: Karnataka’s Chief Minister Siddaramaiah had announced to abolish the tax on agricultural income while presenting the State Budget for 2016-17. This, in turn, will provide relief to many tea and coffee companies besides thousands of individual coffee growers. Plantation companies had to pay a 35 percent tax on their net income.
QUESTION: 75

The Ghatampur thermal power plant recently approved by Cabinet is to be setup in –

Solution: Ghatampur Thermal Power Station is an upcoming coal-based thermal power plant located in Ghatampur in Kanpur district, Uttar Pradesh.
QUESTION: 76

How many languages have recognized by the Constitution—

Solution: The Eighth Schedule to the Indian Constitution contains a list of 22 scheduled languages.
QUESTION: 77

Which atmospheric layer is located at the minimum height from the Earth?

Solution: The troposphere is the lowest layer of Earth’s atmosphere and is also where nearly all weather conditions take place. It contains approximately 75% of the atmosphere’s mass and 99% of the total mass of water vapor and aerosols.
QUESTION: 78

The Himalayas is the example of _________.

Solution: Fold mountains are mountains formed from the folding of the earth’s crust. Fold mountains are formed when two plates move together (a compressional plate margin). This can be where two continental plates move towards each other or a continental and an oceanic plate. The Himalayas is an example of the Fold mountains.
QUESTION: 79

How many Fundamental Duties are mentioned in the Indian constitution?

Solution: The Fundamental Duties of citizens were added to the Constitution by the 42nd Amendment in 1976, upon the recommendations of the Swaran Singh Committee that was constituted by the government earlier that year. Originally ten in number, the Fundamental Duties were increased to eleven by the 86th Amendment in 2002.
QUESTION: 80

Which of the following articles/Articles cannot be suspended even during an emergency?

Solution: The 44th amendment of the constitution took place in 1978, and article 359 was amended, and it provided that articles 20&21 could not be suspended even during the declaration of emergency.
QUESTION: 81

The rule of law is one of the fundamental principles of the UK’s unwritten or uncodified constitution.

Solution: The Westminster system is a parliamentary system of government developed in the United Kingdom. This term comes from the Palace of Westminster, the seat of the British Parliament. The system is a series of procedures for operating a legislature.
QUESTION: 82

“Quwwat-ul-Islam” Mosque was built by

Solution: Quwwat-ul-Islam Mosque is situated near the Qutub Minar in New Delhi. Quwwat-ul-Islam mosque (Might of Islam) (also known as the Qutub Mosque or the Great Mosque of Delhi) was built by Qutb-ud-din Aibak, founder of the Mamluk or Slave dynasty.
QUESTION: 83

The Government of India Act, 1919 is also known as

Solution: The Government of India act 1919 was passed on the basis of recommendations of Lord Chelmsford and Samuel Montagu to introduce self-governing institutions gradually to India. This act covered 10 years, from 1919 to 1929.
QUESTION: 84

The title ‘Indian Napoleon’ has been attached to

Solution: Samudragupta (335-375 AD) of the Gupta dynasty is known as the Napoleon of India. Historian A V Smith called him so because of his great military conquests known from the ‘Prayag Prashasti’ written by his courtier and poet Harisena, who also describes him as the hero of a hundred battles.
QUESTION: 85

Political right does NOT include which of the following?

Solution: The Constitution of India provides Fundamental Rights under Chapter III. Article 21. Protection Of Life And Personal Liberty: No person shall be deprived of his life or personal liberty except according to procedure established by law.
QUESTION: 86

Which of the following appointments is NOT made by the President of India?

Solution: Serving for a term of five years, the Speaker is chosen from amongst the members of the Lok Sabha and is by convention a member of the ruling party or alliance.
QUESTION: 87

External debt is the portion of a country’s debt that was-

Solution: External debt is the portion of a country’s debt borrowed from foreign lenders, including commercial banks, governments, or international financial institutions.
QUESTION: 88

Which institution is known as the ‘Soft Loan Window’ of the World Bank?

Solution: The International Development Association (IDA) is an international financial institution that offers concessional loans and grants to the world’s poorest developing countries. So, it is called the Soft Loan Window of the World Bank. The IDA is a member of the World Bank Group and is headquartered in Washington, D.C., United States.
QUESTION: 89

Which of the following was built by Akbar to commemorate his conquest of Khandesh in Gujarat?

Solution: Buland Darwaza, or the “Gate of victory,” was built in 1601 A.D. by Akbar to commemorate his victory over Gujarat. It is the main entrance to the palace at Fatehpur Sikri, a town which is 43 km from Agra, India.
QUESTION: 90

The Equator does not pass through which of the following?

Solution: the Equator passes through the land of a total 11 countries of the world viz. São Tomé & Príncipe, Gabon, Republic of Congo, Democratic Republic of Congo, Uganda, Kenya, Somalia, Indonesia, Ecuador, Colombia, and Brazil.
QUESTION: 91

Rashtrapati Bhavan was designed by—

Solution: The Rashtrapati Bhavan was designed by Edwin Lutyens and built in 1931 to be the central point of British power in Delhi. (Originally called the Viceroy’s House)
QUESTION: 92

The largest irrigation canal in India is __________.

Solution: The Indira Gandhi Canal is the longest canal in India and one of the largest irrigation projects in the world. Indira Gandhi Canal is 649 km long and consists of Rajasthan feeder canal and Rajasthan main canal and runs through 167 km in Punjab and Haryana and remaining 492 km in Rajasthan.
QUESTION: 93

Which fundamental right is called the heart and soul of the Indian Constitution?

Solution: Dr. B.R.Ambedkar called ‘Article 32’ of the Indian Constitution, i.e., Right to Constitutional remedies, as ‘the heart and soul of the Constitution.’
QUESTION: 94

Which one of the following is not a non-conventional source of energy?

Solution: Natural Gas is a conventional source of energy and not a non-conventional source of energy.
QUESTION: 95

The Delhi Sultan, who fell to his death while playing polo, was

Solution: In 1210, Qutb-ud-din Aibak died in an accident while he was playing polo. He fell from a horse and was severely injured. He was buried in Lahore near the Anarkali Bazaar.
QUESTION: 96

Article 1 of the Constitution declares India as—

Solution: Article 1 in the Constitution states that India that is Bharat, shall be a Union of States. The territory of India shall consist of: The territories of the states, The Union territories, and Any territory that may be acquired.
QUESTION: 97

Among the following States, _________has the lowest birth rate in India.

Solution: Kerala has the lowest birth rate of 14.7, according to the latest official data. Bihar has the highest birth rate.
QUESTION: 98

The “Rule of law” is the specialty of which of the following-

Solution: The rule of law is one of the fundamental principles of the UK’s unwritten or uncodified constitution.
QUESTION: 99

In which session of the Indian National Congress, the tricolor flag was unfurled for the first time?

Solution:

On the midnight of December 31, 1929, and January 1, 1930, the deadline of the Nehru Committee report expired, and Jawahar Lal Nehru unfurled the Flag of India’s independence on the bank of River Ravi in Lahore.

QUESTION: 100

The imaginary lines connecting the places of the same temperature are called-

Solution: Isotherm (contour line) – a type of equal temperature at a given date or time on a geographic map.
QUESTION: 101

Separation of flow occurs when pressure gradient:

Solution:
  • Flow separation occurs when the boundary layer travels far enough against an adverse pressure gradient that the speed of the boundary layer relative to the object falls almost to zero.
  • It has been observed that the flow is reversed in the vicinity of the wall under certain conditions.

  • A favourable pressure gradient is one in which the pressure decreases in the flow direction (i.e., dp/dx < 0)="" />
  • It tends to overcome the slowing of fluid particles caused by friction in the boundary layer.
  • This pressure gradient arises when the freestream velocity U increases with x, for example, in the converging flow field in a nozzle.
  • On the other hand, an adverse pressure gradient is one in which pressure increases in the flow direction (i.e., dp/dx > 0)
  • It will cause fluid particles in the boundary layer to slow down faster than that due to boundary-layer friction alone.
  • If the adverse pressure gradient is severe enough, the fluid particles in the boundary layer will actually be brought to rest.
  • When this occurs, the particles will be forced away from the body surface (a phenomenon called flow separation) as they make room for following particles, ultimately leading to a wake in which flow is turbulent.

QUESTION: 102

Differential manometer is used to measure

Solution: Differential manometers are devices used for measuring the difference of pressures between two points in a pipe or in two different pipes. A differential manometer consists of a U-tube containing a heavy liquid, whose two ends are connected to the points, whose difference of pressure is to be measured. The most common types of differential manometers are
  1. U-tube differential manometer

  2. Inverted U-tube differential manometer

QUESTION: 103

A circular bar 20 mm in diameter and 200 mm long is subjected to a force of 20 kN. Find the strain in the bar if the value of E = 80 GPa.

Solution: E = 80 GPa = 80 × 103 MPa = 80 × 103 N/mm2

Stress = Load/Area

Strain = Stress/E

QUESTION: 104

In a kinematic chain, the relation in the number of links (L) and the number of joints (J) is

Solution: The kinematic pairs are coupled so that the last link is joined to the first link to transmit definite motion (i.e., completely or successfully constrained motion); it is called a kinematic chain.

J = 3/2 L - 2

Another relation between the number of pairs (p) the and number of links(L) is

L = 2p - 4

QUESTION: 105

Kinematic pairs are those which have two elements that

Solution: The two links or elements of a machine, when in contact with each other, are said to form a pair. If the relative motion between them is completely or successfully constrained, the pair is known as a kinematic pair.

QUESTION: 106

A p-V diagram has been obtained from a test on a reciprocating compressor. Which of the following represents that diagram?

Solution: Working of single stage reciprocating air compressor

The compressor operates on a two-stroke cycle:

Stroke 1 (a – c): The piston withdraws, causing the air in the clearance volume to expand, and when the pressure in the cylinder falls below atmospheric pressure (at b), the inlet valve opens, and the air is drawn into the cylinder for the remainder of the stroke.

Stroke 2 (c – a): The piston moves inwards, compressing the air in the cylinder, and the inlet valve closes when the cylinder pressure reaches atmospheric pressure.

Further compression follows as the piston moves toward the top of its stroke until, when the pressure in the cylinder is more than that in the receiver, the delivery valve opens. The air is delivered to the receiver for the remainder of the stroke.

Effect of suction and discharge side pressure drops on P-V diagram of a reciprocating compressor.

Typical indicator card

QUESTION: 107

For forward inclined vanes, i.e., vanes having exit angle greater than 90°, which of the following curves holds good?

Solution:

Radial vanes, Backward vanes, Forward vanes

Backward Curved Blades: vane exit angle is less than 90°

Forward Curved Blades: vane exit angle is more than 90°

Radial Blades: Vane exit angle is 90°

The blades of the compressor or either forward-curved or backward-curved or radial. Back curved blades were used in the older compressors, whereas the modern centrifugal compressors use mostly radial blades.

Pumps are not usually designed with forward curved vanes since such pumps tend to suffer unstable flow conditions.

Backward curved blades are slightly better inefficiency and are stable over a wide range of flow. While forward-curved blades are used for a higher pressure ratio.

Head-capacity and power-capacity curves

QUESTION: 108

Quicksand comes under:

Solution: Newtonian Fluids: Air, water, mercury, glycerine, kerosene, and other engineering fluids under normal circumstances.

Pseudoplastic: Fine particle suspension, gelatine, blood, milk, paper pulp, polymeric solutions such as rubbers, paints.

Dilatant fluids: Ultrafine irregular particle suspension, sugar in water, an aqueous suspension of rice starch, quicksand, butter printing ink.

Ideal plastics or Bingham fluids: Sewage sludge, drilling muds.

Viscoelastic fluids: Liquids solid combination in pipe flow, bitumen, tar, asphalt, polymerized liquids with drag reduction features.

Thixotropic: Printer’s ink, crude oil, lipstick, certain paints, and enamels.

Rheopectic fluids: Very rare liquid-solid suspensions, gypsum suspension in water, and bentonite solutions.

QUESTION: 109

Fire tube boilers are generally

Solution: Fire Tube boiler: In this boiler, the hot flue gases are present inside the tubes, and water surrounds them. They are low-pressure boilers. The operating pressure is about 25 bar.

Example to fire tube boilers:

  • Cornish boiler

  • Cochran boiler

  • Locomotive boiler

  • Lancashire boiler

  • Scotch marine boiler

Water Tube Boiler: In this boiler, water is present inside the tubes, and the hot flue gases surround them. They are high-pressure boilers. The operating pressure is about 250 bar.

Examples of water tube boilers:

  • Stirling boiler

  • Babcock and Wilcox boiler

  • Yarrow boiler

  • La mont boiler

  • Loeffler boiler

  • Velox boiler

QUESTION: 110

Ductility of a material can be defined as

Solution:

Ductility

Ductility is the property of the material that enables it to be drawn out or elongated to an appreciable extent before rupture occurs.

The percentage elongation or percentage reduction in the area before rupture of a test specimen is the measure of ductility. Normally if the percentage elongation exceeds 15%, the material is ductile, and if it is less than 5%, the material is brittle.

Lead, copper, aluminium, mild steel are typical ductile materials.

Brittleness

Brittleness is the opposite of ductility. Brittle materials show little deformation before fracture and failure occur suddenly without any warning, i.e., it is the property of breaking without much permanent distortion. Normally if the elongation is less than 5%, the material is brittle. E.g., cast iron, glass, ceramics are typical brittle materials.

Malleability

Malleability is the property by virtue of which a material may be hammered or rolled into thin sheets without rupture. This property generally increases with the increase of temperature.

Malleability is the ability of a metal to exhibit large deformation or plastic response when being subjected to compressive force.

Lead, soft steel, wrought iron, copper, and aluminium are some materials in order of diminishing malleability.

QUESTION: 111

The period (T) for the pendulum with length (l) and placed at the gravitational acceleration (g) is given by:

Solution: The time period (T) of a pendulum is the time taken by the pendulum to complete one oscillation, and it is given by

Where l is the length of the pendulum and g is the acceleration due to gravity.

QUESTION: 112

Tempering of steel is done to make it

Solution: Tempering is a heat treatment process in which the appropriate heat treatment process reduces the hardness of a hardened alloy; for example, steel hardened by the formation of martensite formation can be tempered.

Tempering is a heat-treatment process consisting of reheating the hardened steel to a temperature below 400°C, followed by cooling.

Purpose of tempering the steel

Steel in its hardened condition is generally too brittle to be used for certain functions. Therefore, it is tempered. The aims of tempering are:

  • to relieve the internal stresses

  • to regulate the hardness and toughness

  • to decrease the brittleness

  • to restore some ductility

  • to induce shock resistance

QUESTION: 113

Polytropic index n is given

Solution:

Taking log

log(p2/p1)/log(v1/v2)

QUESTION: 114

The square root of the ratio between the inertia force and gravity force is called ________.

Solution:

QUESTION: 115

One bar unit of Pressure =?

Solution:

1 Bar = 101325 Pascal

1 Bar = 101.325 Kilo Pascal

QUESTION: 116

‘Block’ used in AutoCAD (TB) holds an important role in productivity; Block is a(an)

Solution: In AutoCAD, a block is a collection of objects combined into a single named object. Block represents a repeatable item used in drawing.

Advantages of Blocks:

  • It increases the speed of drawing creation

  • Using block greatly reduces the file size of saved drawing

  • Blocks help in keeping consistency in project drawing, thus avoiding confusions

QUESTION: 117

Main purpose of normalizing is to

Solution: Normalizing: Heat the steel from 30°C to 50°C above its upper critical temp, held about fifteen minutes, and then allowed to cool down in still air. The homogeneous structure provides a higher yield point, ultimate tensile strength, and impact strength with lower ductility to steels.

The main purpose of normalizing is to refine grain size.

Main objective

1. Refine grain size in metal, improve strength and hardness, reduce ductility

2. Remove cold worked stress.

3. Remove dislocations due to hot working.

QUESTION: 118

Automobile Steering gear is an example of

Solution: When the two elements of a pair have a surface contact when relative motion takes place, and the surface of one element slides over the surface of the other, the pair formed is known as a lower pair. Automobile Steering gear is an example of Lower pair.
QUESTION: 119

Which of the following is measured in the poise?

Solution: (1) Dynamic viscosity: This is also termed as absolute viscosity. A common unit of dynamic viscosity is poise.

1 poise = 0.1 Pa.s = 0.1 N.s/m2

(2) Kinematic Viscosity: The ratio of dynamic viscosity to density appears frequently, and this ratio is given by the name kinematic viscosity. Its unit is Stoke or m2/s (1 stoke = 0.0001 m2/s)

(3) Unit of the velocity of flow is m/second.

(4) Unit of discharge of flow is m3/second.

QUESTION: 120

Stainless steel is so-called because of its _________.

Solution:

Stainless steels typically contain 10 - 30 % chromium besides other elements like C, Mn, Si, S, etc. Chromium imparts corrosion resistance to steel. Varying amounts of other alloying elements like Ni, Mo, V, Ti, Ni, etc., may be added to obtain certain low-grade properties.

It exhibits extraordinary corrosion resistance due to the formation of a very thin layer of Cr2O3 on the surface.

One important type of stainless steel is often described as 18/8 steel, where chromium and nickel percentages are 18 and 8, respectively.

QUESTION: 121

The temperature at which the new grains are formed in the metal is called

Solution: Recrystallisation is the process in which deformed grains are replaced by strain-free grains. It is generally observed that higher cold work and smaller initial grain size lead to finer recrystallized grains. The driving force for recrystallisation is the stored strain energy in the material.

The temperature at which a given material is completely recrystallised in an hour is defined as the recrystallisation temperature.

The recrystallisation temperature is low if the degree of deformation is high and if the temperature of deformation is low, and/or if the initial grain size is small. The recrystallisation temperature is also very sensitive to the purity of the material.

QUESTION: 122

Oldham’s coupling is an inversion of

Solution: Oldham’s coupling is an inversion of the double slider-crank mechanism. An Oldham coupler is a method to transfer torque between two parallel but not collinear shafts at some distance.

There are three important inversions of the double slider crank chain.

1) Elliptical trammel

2) Scotch yoke mechanism

3) Oldham‘s Coupling

QUESTION: 123

What is the safe working pressure for a spherical pressure vessel 1.5 m internal diameter and 1.5 cm wall thickness if the maximum allowable tensile stress is 45 MPa?

Solution: For thin spherical vessel:

For a thin spherical pressure vessel, both longitudinal and hoop stress is the same and given as

QUESTION: 124

The difference between the total headline and the hydraulic grade line represents

Solution: Hydraulic gradient Line (H.G.L.) – Line representing the sum of pressure head and datum head.

Total energy line (T.E.L.) – Line representing the sum of pressure head, datum head, and velocity head.

∴ T.E.L. – H.G.L. = velocity head

QUESTION: 125

Mohr’s circle can be used to determine the following stress on an inclined surface:

A. Principal stress

B. Normal stress

C. Tangential stress

D. Maximum shear stress

Solution: Mohr circle is a graphical representation of plane stress which helps in determining the relationships between normal, and shear stresses acting on an inclined plane at a point in a stressed body.

Mohr’s circle of stresses is a graphical method of finding normal, tangential, and resultant stresses on an oblique plane.

QUESTION: 126

The value of for an irreversible cycle is

Solution: From Clausius inequality

QUESTION: 127

A moving fluid mass may be brought to a static equilibrium position by applying an imaginary inertia force of the same magnitude as that of the accelerating force but in the opposite direction. This statement is called

Solution: Newton's second law:

F = ma

F + (-ma) = 0

We can say that the body is in equilibrium under the action of external forces (F) and inertial force (-ma).

This is D’Alembert’s principle which states that a moving body can be brought to equilibrium by adding inertia force Fi to the system.

In magnitude, this inertia force is equal to the product of mass and acceleration and takes place in a direction opposite to that of acceleration.

QUESTION: 128

The stagnation pressure is the _________

Solution: Stagnation Pressure (Po) is the pressure at the stagnation point at which velocity is zero as the kinetic head is completely converted to static head. Thus, stagnation pressure is the sum of static pressure (P) and dynamic pressure (ρ V2/2).

∴ Po = P + ρV2/2

QUESTION: 129

What is the resistance of the material to deflection known?

Solution: Stiffness is the resistance of an elastic body to deflection or deformation by an applied force.

The stiffness, k, of a body is a measure of the resistance offered by an elastic body to deformation. For an elastic body with a single degree of freedom (DOF) (for example, stretching or compression of a rod),

the stiffness is defined as

rm k = rmF/rmδ

where,

F is the force on the body

δ is the displacement produced by the force along the same degree of freedom

The resistance of the material to deflection is known stiffness.

QUESTION: 130

The power transmitted by a circular shaft rotating at N rpm under the action of torque T is:

Solution: In S.I units, power transmitted (in watts) by the shaft,

P = 2πNT/60

In M.K.S units, horsepower transmitted by the shaft,

P = 2πNT/4500

Out of the given 4 options, only one option is the correct formula for power transmitted.

QUESTION: 131

Name the part of a lathe machine that provides the method of holding and moving the cutting tool

Solution: Lathe is a machine tool that holds the job between the centre and base and rotates the job, and rotates the job on its own axis.

Main parts of Lathe:

QUESTION: 132

Lathe bed is usually made of_______.

Solution: Lathe is a machine tool that holds the job in between the centre and base and rotates the job, and rotates the job on its own axis.

Main parts of Lathe:

QUESTION: 133

Tolerances for a hole and shaft assembly having a nominal size of 40 mm are as follows :

Determine the Maximum material Limit (MML) of the hole.

Solution: The maximum material Limit (MML) in case of the hole is the lower limit of the hole.

Or the 'GO' condition,

Given dimension of hole =

base size of hole = 40 mm

upper limit of hole = 40 + 0.06 = 40.06 mm

lower limit of hole = 40 + 0.02 = 40.02 mm

So MML for hole = lower limit of hole

= 40 + 0.02 = 40.02;mm

and 'NO GO' condition or minimum material limit or the upper limit of hole = 40.06 mm

QUESTION: 134

The four process of the Carnot cycles are

Solution: Carnot cycle consists of two reversible isothermal processes and two isentropic processes.

Carnot cycle is one of the best-known reversible cycles. The Carnot cycle is composed of four reversible processes.

  • Reversible Isothermal Expansion (process 1-2)
  • Reversible adiabatic expansion (process 2-3)
  • Reversible isothermal compression (process 3-4)
  • Reversible adiabatic compression (process 4-1)

Fig. P-V and T-S diagrams of Carnot Cycle

QUESTION: 135

An ideal gas undergoes an isothermal expansion from state R to state S in the turbine, as shown in the diagram given below:

The area of the shaded region is 1000 N-m. The amount is turbine work done during the process is

Solution: The area under the P-V diagram gives work done.

Turbine work = Area under curve R-S = Area of Rectangle + Area of the shaded region.

W = (0.2 – 0.1) × 1 × 105 + 1000

W = 11000 N – m

QUESTION: 136

Work is considered to be a superior form of energy as compared to heat energy because,

Solution: Based on the thermodynamic concepts, an energy source can be called high-grade or low-grade, depending on the ease with which it can be converted into other forms.

Thus electrical energy (or work) is called a high - grade energy, as it is very easy to convert almost all of it into other energy forms such as thermal energy (say by using an electrical heater). Whereas it is not possible to completely convert thermal energy (or heat) into electrical energy (typical efficiencies of thermal power plants around 30 percent), thermal energy is called low-grade energy.

QUESTION: 137

In reciprocating engines primary forces _________.

Solution: In the case of reciprocating masses, Primary forces are partially balanced. Because in the reciprocating masses, "the resultant forces" will be completely balanced, but "the resultant couple" won't be balanced; that is why we call reciprocating masses only partially balanced.

Since reciprocating mass cannot balance fully, partial balancing of the reciprocating mass is done while revolving masses can be balanced fully.

Primary unbalanced Force FP = mrω2cos2θ

Secondary unbalanced Force = FS = mrω2cos2θ/n

Effect of Partial Balancing of Reciprocating Parts

Reciprocating parts are only partially balanced. Due to this partial balancing of the reciprocating parts, there is an unbalanced primary force along the line of stroke and an unbalanced primary force perpendicular to the stroke line. The effect of an unbalanced primary force along the line of stroke is to produce;

  • Variation in tractive force along the line of stroke

  • Swaying couple

QUESTION: 138

In limiting friction, the resultant reaction R, the normal reaction N, and angle of friction θ, are related as

Solution:

F is the frictional force developed, and N is the normal reaction.

The direction of resultant R measured from the direction of N is specified by tan θ = F/N

μ = tanθ = F/N

Here F = R sin θ

N = R cos θ

Where θ is angle of friction.

QUESTION: 139

A diathermic wall is the one which:

Solution: A diathermal or diabatic wall is one that heat can pass through. It is made from a thermal conductor. It is essentially a thermal wall.

An adiabatic wall is one that heat cannot pass through. It is made from a thermal insulator.

QUESTION: 140

The value obtained from dividing the limiting value of circulation by area of closed contour is known as _______.

Solution: Stream Function: It is a scalar function of space and time. Its partial derivative with respect to any direction gives the velocity component at right angles (in a counter-clockwise direction) in this direction.

Potential Function: A scalar function of space and time such that its negative derivative with respect to any direction gives the fluid velocity in that direction.

Circulation: It is the line integral of the tangential component of the velocity taken around a closed contour.

Vorticity: The limiting value of circulation divided by the area of closed contour, as the area tends to zero.

∴ The value obtained from dividing the limiting value of circulation by area of closed contour is known as vorticity.

QUESTION: 141

What is the expression for crippling load for a column with both ends hinged?

Solution: Euler’s load or crippling load for a column of different end conditions is given by

rm Prm E =

Where,

PE = Euler’s crippling load, E = Young’s Modulus of elasticity, I = Moment of inertia of the column section, and Leff = Effective length of the column

For column having both ends hinged, Leff = L

QUESTION: 142

Which of the following is the important mechanical property for a material to be forged or rolled into thin sheets successfully?

Solution:

Malleability

Malleability is the property by virtue of which a material may be hammered or rolled into thin sheets without rupture. This property generally increases with the increase of temperature.

Malleability is the ability of a metal to exhibit large deformation or plastic response when being subjected to a compressive force.

Ductility

Ductility is the property of the material that enables it to be drawn out or elongated to an appreciable extent before rupture occurs.

Brittleness

Brittleness is the opposite of ductility. Brittle materials show little deformation before fracture and failure occur suddenly without any warning, i.e., it is the property of breaking without much permanent distortion.

QUESTION: 143

The process of making a cone-shaped enlargement of the end of a hole is:

Solution: Spot Facing: It is an operation of smoothing and squaring the surface around a hole for the seat for the nut or the head of a screw.

Counterboring: It is an operation of enlarging a drilled hole partially for a drilled hole.

Countersinking: It is an operation of forming a conical shape at the end of a drilled hole.

Trepanning: It is an operation of producing a hole by removing the metal along the circumference of a hollow cutting tool.

QUESTION: 144

If air is heated without changing its moisture content, the dew point will _____.

Solution: Concept

Dry Bulb Temperature: Actual temperature of gas or mixture of gases.

Wet-bulb temperature: Temperature obtained by an accurate thermometer having a wick moistened with distilled water.

Dew point temperature: Temperature at which the liquid droplets just appear when the moist air is cooled continuously.

Sensible heating: Moisture content of air remains constant, so specific humidity is constant, temperature increases as it flows over a heating coil.

Sensible cooling: The moisture content of air remains constant, so specific humidity is constant, but its temperature decreases as it flows over a cooling coil.

According to the question:

If air is heated without changing its moisture content, ⇒ Sensible heating.

Sensible heating: It is the process of increasing the Dry bulb temperature at a constant specific humidity.

Effects of sensible heating:

  • Dry bulb temperature increases
  • Sp. Humidity or humidity ratio remains constant
  • Dew point temperature is constant
  • Relative humidity decreases
  • Enthalpy increases
  • Specific Volume Increases
  • Wet-bulb temperature increases

QUESTION: 145

The kinetic energy of a flywheel, having a moment of inertia I and angular speed ‘ω,’ is given by

Solution: Kinetic energy of the flywheel is given by

K.E = 1/2Iω2 = 1/2mk22

I is the mass moment of inertia of the flywheel about its axis of rotation in kg-m2 = m.k2.

QUESTION: 146

The property of a fluid that enables it to resist tensile stress is known as

Solution: Cohesion: The force of attraction between the molecules of a liquid by virtue of which they are bound to each other to remain as one assemblage of particles is known as the force of cohesion. This property enables the liquid to resist tensile stress.

Adhesion: The force of attraction between unlike molecules, i.e., between the molecules of different liquids or between the molecules of a liquid and those of a solid body when they are in contact with each other, is known as the force of adhesion. This force enables two different liquids to adhere to each other or a liquid to adhere to a solid body or surface.

Surface tension is the elastic tendency of a liquid surface, which makes it acquire the least surface area possible. It occurs at the interface of two liquids due to the intermolecular force of cohesion.

Compressibility is the ability of fluid to change its volume under pressure.

QUESTION: 147

To avoid separation, the most suitable ratio of throat diameter and pipe diameter in a venturi meter is ______.

Solution: Venturi meter: Venturi meter is a device used to measure the flow rate of a fluid flowing through a pipe.

The working of the venturi meter is based on the principle of Bernoulli’s equation.

The Venturi meter is divided into 3 parts:

  1. Convergent cone

  2. Divergent cone

  3. Throat

Important Point:

Convergent cone:

The angle of convergence is generally 20-22 degrees.

The length of the convergent cone is 2.7(D-d).

Here 'D' is the diameter of the inlet section, and 'd' is the diameter of the throat.

Throat:

The length is equal to the diameter of the throat.

Generally, the diameter of the throat is 1/3 to 3/4 of the diameter of the inlet pipe.

Diverging cone:

The diverging section has an angle of 5 to 15 degrees.

The diverging angle is less than the converging angle.

Although the desirable ratio of throat diameter and pipe diameter lies between 1/3 to 3/4.

The most appropriate option is 0.33 to 0.5, as the energy losses would minimize if the area difference is minimized.

QUESTION: 148

A thin cylindrical shell under internal pressure can fail along the

Solution: Type of failure:

Such a component fails when subjected to an excessively high internal pressure. While it might fail by bursting along a path following the circumference of the cylinder. Under normal circumstances, it fails by bursting along a path parallel to the axis. This suggests that the hoop stress is significantly higher than the axial stress.

When a thin cylindrical shell is subjected to internal pressure, it is likely to fail in the following two ways:

1. It may fail along the longitudinal section (i.e., circumferentially), splitting the cylinder into two troughs

2. It may fail across the transverse section (i.e., longitudinally), splitting the cylinder into two cylindrical shells

Failure of a cylindrical shell along the longitudinal section and Failure of a cylindrical shell along the transverse section

QUESTION: 149

Size of the shaper is specified by

Solution: Shaping, planning, and slotting operations are similar machining processes that provide a cutting action due to straight-line reciprocating motion between the tool and the work. In all the processes, single-point cutting tools are used.

In shaping and planning operations, straight and flat surfaces are created. In shaping operation, the speed motion is accomplished by moving the cutting tool, while in planning, the motion is accomplished by the workpiece. Shaping is performed in a machine tool called a shaper, whereas the machine tool for planning is called a planer. The slotting process is identical to shaping except that the motion of the ram is vertical instead of horizontal.

The size of the shaper is specified by the maximum length of stroke or cut it makes. The maximum stroke length of the shaper is 900 mm.

QUESTION: 150

________ is a transmission dynamometer -

Solution: A dynamometer is a device used for measuring the torque and brake power required to operate a driven machine. It has an instrument to measure frictional resistance.

Following are the two types of dynamometers used for measuring the brake power of an engine.

1. Absorption dynamometers: The entire energy or power produced by the dynamometer is absorbed by the friction resistance of the brake and is transformed into heat during the process of measurement.

Example: Prony brake dynamometer, Rope brake dynamometer, Hydraulic dynamometer

2. Transmission dynamometers: The energy is not wasted in friction but is used for doing work. The energy or power produced by the engine is transmitted through the dynamometer to some other machines where the power developed is suitably measured.

Example: Epicyclic-train dynamometer, Belt transmission dynamometer, Torsion dynamometer.

QUESTION: 151

In gears, interference takes place when _____.

Solution: Due to interference, the tip of one of the gears of the pair will tend to dig into portions of the flank of the tooth of the other member of the pair.

Methods of elimination of Gear tooth Interference:

  • Use of a larger pressure angle (having a larger pressure angle results in a smaller base circle. As a result, more of the tooth profiles become involute)

  • Under-cutting of the tooth (A portion of teeth below the base circle is cut off. When teeth are produced by this process, the tip of one tooth of gear will not contact the non-involute portion of the tooth of other gear)

  • Tooth stubbing (In this process, a portion of the tip of the teeth is removed, thus preventing that portion of the tip of the tooth from contacting the non-involute portion of the other meshing tooth).

  • Increasing the number of teeth on the gear can also eliminate the chances of interference.

  • Increasing the center distance between the meshing gears slightly eliminates interference.

  • Tooth profile modification or profile shifting (Using profile shifted gears (gears with non-standard profile) can also be an option to eliminate interference. In profile shifted meshing gears, the addendum on the pinion is shorter compared with standard gears).

QUESTION: 152

Transmission angle is the angle between

Solution:

The transmission angle is the angle between the output link and the coupler. If the value of the transmission angle is zero, then the mechanism will lock or jam. If the transmission angle deviates from the 90O, then the torque on the output link decreases. So usually, the value of this angle is kept at more than 45O. The best mechanism is in which the transmission angle does not deviate much from the 90O.

QUESTION: 153

The force induced in the string BC due to the load W, as shown in the figure, is

Solution: FAB sin θ = W

FAB = W cosec θ

FBC = FAB cos θ = W cosec θ × cos θ

FBC = = W cot θ

QUESTION: 154

When a real gas undergoes Joule-Thomson expansion, the temperature

Solution: Joule – Thomson coefficient:- When the gas in steady flow passes through a construction, e.g., in an orifice or valve, it normally experiences a temperature change. From the first law of thermodynamics, such a process is isenthalpic, and one can usually define a Joule – Thomson coefficient as

The numerical value of the slope of an isenthalpic on a T-p diagram at any point is called the Joule-Thomson coefficient and is denoted by μj

A measure of the change in temperature results from a drop in pressure across the construction.

If μ is +ve, then the temperature will fall during throttling.

So from the figure, it is clear that temperature may increase or decrease it will depend on the value of μ.

QUESTION: 155

Water is pumped through a pipeline to a height of 10 m at a rate of 0.1 m3/s. If frictional and other losses amount to 5 m, the pumping power required in kW would be

Solution: Power = ρQgH

Where H is a totally effective head.

P = 1000 × 0.1 × 9.81 × (10 + 5) = 14715 W = 14.7 kW

QUESTION: 156

A block of wood floats in water with 2/3rd of its volume submerged. Its relative density is:

Solution: According to Archimedes Principle, when a body is fully or partially immersed in a liquid, the amount of liquid displaced by the body is equal to the loss of weight of the body in the liquid.

∴ Weight of wooden block = Weight of the volume of fluid displaced

Let,

The density of wooden block = γb, the density of water = γw, and volume of block = V

Weight of wooden block = γb × V

Weight of the volume of fluid displaced = γw × 2/3 × V

γb × V = γw × 2/3 × V

∴ γb = 2/3 × γw

∴ The relative density for the wooden block is γb/γw = 2/3.

QUESTION: 157

Match List – I (Measuring device) with List-II (Parameter measured) and select the correct answer using the options given below the lists:

Solution: Anemometer: It is used to measure the velocity of the wind or of any other gases passing through.

Piezometer: It is used to measure the static pressure of the fluid at any section.

Pitot tube: It is used to calculate the dynamic pressure (total pressure – static pressure) in any section.

Orifice meter – It is used to measure the discharge of fluid across a considered section.

QUESTION: 158

The coefficient of discharge, Cd in terms of Cv and Cc is given by (Notations have their usual meaning)-

Solution: The coefficient of discharge (Cd) is given by

Cd = Cc × Cv

Where,

Cc = Coefficient of contraction

Cv = Coefficient of velocity

QUESTION: 159

What is the value of the angle (degree) between streamlines and equipotential lines at the point of intersection in the flow net?

Solution: The angle between streamlines and equipotential lines at a point of intersection in the flow net is always intersect at 90°

QUESTION: 160

Which solution is used in an ice plant?

Solution: There are three main circuits of working medium in ice plant

Refrigeration circuit: Ammonia as working medium (primary refrigerant) produces the cold by changing its phase at different locations.

Cooling water circuit: Cooling water as a working medium to remove the heat of the condenser.

Brine circuit: Brine solution as a working medium which transfers the cold from ammonia to water-filled cans where ice is to be formed.

QUESTION: 161

Mathematical expression for Modulus of Resilience is_______. (E is Young’s Modulus, ϵ is strain)

Solution: Strain Energy of the member is defined as the internal work done in deforming the body by the action of externally applied forces.

Resilience is defined as the capacity of a strained body for doing work on the removal of the straining force.

Proof resilience is defined as the maximum strain energy stored in a body. So, it is the quantity of strain energy stored in a body when strained up to an elastic limit (ability to store or absorb energy without permanent deformation).

Modulus of resilience is defined as proof resilience per unit volume. It is the area under stress–strain curve up to the elastic limit.

QUESTION: 162

The deflection of a simply supported rectangular beam is:

Solution: Deflection of simply supported beam

Concentrated load P at the center,

Uniformly distributed load w (N/m),

I = bd3/12

QUESTION: 163

Figure out the odd point in the following

Solution: Proportional limit, Elastic limit, and yield point are points before metal failure, but fracture point is a point of failure where metal fractures.

  • So it is evident from the graph that the strain is proportional to stress or elongation is proportional to the load giving a straight-line relationship. This law of proportionality is valid up to a point A. Point A is known as the limit of proportionality or the proportionality limit.
  • For a short period beyond point A, the material may still be elastic in the sense that the deformations are completely recovered when the load is removed. The limiting point B is termed as Elastic Limit.
  • Beyond the elastic limit, plastic deformation occurs, and strains are not totally recoverable. There will be thus permanent deformation or permanent set when the load is removed. These two points are termed upper and lower yield points, respectively. The stress at the yield point is called the yield strength.
  • A further increase in the load will cause marked deformation in the whole volume of the metal. The maximum load which the specimen can withstand without failure is called the load at the ultimate strength. The highest point ‘E' of the diagram corresponds to the ultimate strength of a material.
  • Beyond point E, the bar begins to form the neck. The load falls from the maximum until a fracture occurs at F.

QUESTION: 164

Cutting tool used in planing machine is

Solution: Like shaping machines, planing machines are also basically used for producing flat surfaces in different planes.

The tools used in planing and shaping are similar to single-point lathe tools, consisting of the shank and the point.

Planing and shaping tools are made of HSS or tipped with cemented carbides.

QUESTION: 165

The coldest part of the domestic refrigerator is

Solution: Working of different parts of the refrigerator are

Compressor: The compressor is located at the back of the refrigerator and in the bottom area. The compressor sucks the refrigerant from the evaporator and discharges it at high pressure and temperature. The compressor is driven by the electric motor, and it is the major power-consuming device of the refrigerator.

Condenser: The condenser is the thin coil of copper tubing located at the back of the refrigerator. The refrigerant from the compressor enters the condenser,stress-strain where it is cooled by the atmospheric air, thus losing heat absorbed by it in the evaporator and the compressor.

Expansive valve or the capillary: The refrigerant leaving the condenser enters the expansion device, which is the capillary tube in domestic refrigerators. The capillary is the thin copper tubing made up of a number of turns of the copper coil. When the refrigerant is passed through the capillary, its pressure and temperature drop down suddenly.

Evaporator or chiller or freezer: The refrigerant at very low pressure and temperature enters the evaporator or the freezer. It is the coldest part of the refrigerator. The refrigerant absorbs the heat from the substance to be cooled in the evaporator, gets evaporated, and is then sucked by the compressor. This cycle keeps on repeating.

Receiver: The primary function of the receiver is to catch and hold any liquid refrigerant that didn’t boil off in the evaporator. Liquid refrigerant getting to the compressor can damage the pistons.

QUESTION: 166

Which of the following is true for a self-locking screw?

Solution: For a self - locking screw, the coefficient of friction is equal to or greater than the tangent of the helix angle.

In the Power screw, the torque Mt required to lower the load is given by

Mt = Wdm/2 tan (ϕ−α) where, W = load on the screw in N, dm = the mean diameter of the screw-in m,

ϕ = friction angle and α = helix angle

Case 1. when ϕ ≥ α

tan (ϕ - α ) ≥ 0, thus Mt ≥ 0.

i.e., positive torque is required to lower the load. Thus the load will not turn the screw and will not descend on its own unless an effort is applied.

Such cases of screws are known as 'Self-locking screws.’ And the screw will hold the hold without any application of the brake.

Also, as ϕ ≥ α

tan ϕ ≥ tan α

Case 2. when ϕ < />

tan (ϕ - α ) < 0,="" thus="" />t < />

i.e., negative torque is required to lower the load. The load will turn down the screw and will descend on its own unless a restoring torque is required to hold the load.

Such cases of screws are known as 'overhauling of the screw' or back drawing of the screw.

QUESTION: 167

Triple point ________.

Solution: The Triple point is a line on the P - v diagram where all the three phases, solid, liquid, and gases, exist in equilibrium. At a pressure below the triple point line, the substance cannot exist in the liquid phase, and the substance, when heated, transforms from solid to vapour by absorbing the latent heat of sublimation from the surroundings.
QUESTION: 168

Which gas among the following has the highest value of the adiabatic index?

Solution: The ratio of CP to CV (CP/CV) for gas is known as the specific heat ratio or adiabatic index and is usually denoted by the Greek letter gamma.
  • For an ideal monatomic gas (e.g., Helium, Argon, etc.), the adiabatic index is 5/3 or 1.67
  • For diatomic gases, the adiabatic index is 7/5 or 1.4
  • For polyatomic gases, the adiabatic index is even lesser than the monoatomic and diatomic gases
  • Out of the given options, Helium is monoatomic, so it have the highest adiabatic index

QUESTION: 169

Specific speed of the hydraulic turbine is dependent upon ____.

Solution: Specific speed: It is defined as the speed of a similar turbine working under a head of 1 m to produce a power output of 1 kW. The specific speed is useful to compare the performance of the various types of turbines. The specific speed differs for different turbines and is the same for the model and actual turbine.

Specific speed of the hydraulic turbine is dependent upon speed, the power developed, and the effect head.

QUESTION: 170

Which one of the following is defined as force per unit length?

Solution: Surface tension is the elastic tendency of a fluid surface, making it acquire the least surface area possible. Surface tension is measured in SI units of N/m (newton per meter). The cohesive forces among liquid molecules are responsible for the phenomenon of surface tension.

Compressibility is a measure of the relative volume change of a fluid or solid as a response to a pressure change. Its unit is Pa-1.

Capillarity or capillary action is the ability of a narrow tube to draw a liquid upwards against the force of gravity. The height of liquid in a tube due to capillarity is expressed in m.

The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress caused due to flow. Its units are Pa·s = (N·s)/m2 = kg/(s·m)

QUESTION: 171

In arc welding, penetration is minimum for

Solution: In arc welding, penetration is minimum for DC – Electrode Positive.

Types and importance of polarity in arc welding

Polarity indicates the direction of current flow in the welding circuit.

Kinds of polarity

  • Straight polarity or electrode negative (DCEN)
  • Reverse polarity or electrode positive (DCEP)

Straight polarity: In straight polarity, the electrode is connected to the negative and the work to the positive terminal of the power source.

Electrode Negative Or straight polarity (DCEN)

Reverse Polarity: In reverse polarity, the electrode is connected to the positive and the work to the negative terminal of the power source.

Electrode Positive Or Reverse Polarity (DCEN)

DCSP (Electrode Negative)—Maximum penetration.

AC—Moderate penetration.

DCRP (Electrode Positive)—Minimum penetration

QUESTION: 172

Hardness of cementite is of the order of _______ BHN

Solution: Cementite is an intermetallic compound of iron and carbon, Fe3C. It is hard and brittle. Carbon content is 6.7%.

The hardness of cementite is around 550 BHN.

The hardness of martensitic steel depends on its carbon content and ranges from about 460 BHN at 0.2% carbon content to about 710 BHN at about 0.5% carbon. The hardness of pearlite is about 240 BHN.

QUESTION: 173

Facing operation is

Solution: Facing is a machining operation by which the end surface of the workpiece is made flat by removing metal from it.

Undercutting/Grooving is the process of reducing the diameter of a workpiece over a narrow surface.

Knurling is an operation of embossing a diamond-shaped pattern on the surface of a workpiece.

Chamfering is the operation of bevelling the extreme end of a workpiece. It is used to remove the sharp edge of the workpiece surface.

QUESTION: 174

In an on-off control refrigeration system, which one of the following expansion devices is used?

Solution: On-off control is done by a thermostat.

In the On-off control of the air-handling unit, the fan motor is operated intermittently by the room thermostat, the bulb of which is installed in the return air.

A thermostatic expansion valve maintains a constant degree of superheat at the exit of an evaporator; hence it is most effective for dry evaporators in preventing the slugging of the compressors since it does not allow the liquid refrigerant to enter the compressor.

QUESTION: 175

A system will be in thermodynamic equilibrium only if it is in ____.

A. Thermal equilibrium

B. Mechanical equilibrium

C. Chemical equilibrium

Solution: The system is said to be in thermodynamic equilibrium if the conditions for the following three equilibrium is satisfied

1) Mechanical equilibrium: When there are no unbalanced forces within the system and between the system and the surrounding, the system is said to be under mechanical equilibrium.

2) Chemical equilibrium: The system is said to be in chemical equilibrium when no chemical reactions are going on within the system. There is no transfer of matter from one part of the system to another due to diffusion.

3) Thermal equilibrium: When the system’s temperature is uniform and not changing throughout the system, and in the surroundings, the system is said to be in thermal equilibrium.

QUESTION: 176

The velocity distribution for flow over a flat plate is given by u = (y - y2), in which u is the velocity in meters per second at a distance of y meters above the plate. What is the shear stress value at y = 0.15 m? The dynamic viscosity of the fluid is 8.0 poise.

Solution: Concept

According to Newton’s law of viscosity, τ = μ(du/dy) the shear stress is directly proportional to the rate of shear strain or rate of angular deformation of a fluid particle.

τ = μ(du/dy)

Calculation:

u = (y - y2)

du/dy = 1−2y

at y = 0.15

du/dy = 1−2(0.15) = 0.70

τ = μ(du/dy) = 0.8 × 0.7 = 0.56;N/m2

Note: 1 poise = 0.1 Ns/m2

QUESTION: 177

Bending moment M and torque T are applied on a solid circular shaft. If the maximum bending stress equals maximum shear stress developed, then M is equal to

Solution: Bending stress due to bending moment

σ = 32M/πd3

Shear stress due to twisting moment/ torque:

τ = 16T/πd3

If the maximum bending stress equals maximum shear stress developed:

QUESTION: 178

COP of a Carnot heat pump operating between -3°C and 27°C is

Solution: Given: TL = -3°C, TH = 27°C

QUESTION: 179

Following type of cam is used for high-speed engine

Solution: Cycloidal motion curve has the best dynamic characteristics. The acceleration is finite at all times, and the starting and ending acceleration is zero. It will yield a cam mechanism with the lowest vibration, stress, noise, and shock characteristics. Hence for high-speed applications, this motion curve is recommended.
QUESTION: 180

In a cam drive, it is essential to offset the axis of a follower to

Solution: When the motion of the follower is along an axis away from the axis of the cam center, it is called an off-set follower.

Follower with zero offsets and Follower with offset

If the follower movement is a displacement from the cam centre, then the follower is called an offset follower, offsetting results in reduced forces and stresses.

The offsetting eccentricity should be in the direction to improve force components tending to jam the translating follower in its bearing guide and decrease the wear between follower and cam surface.

QUESTION: 181

A 5 kg box is raised through a height. Its potential energy increases by 49 J. The height is (g = 9.8 m/s2)

Solution: Potential energy

P.E. = mgh

49 = 5 × 9.8 × h

h = 1.0 m

QUESTION: 182

What does the second law of thermodynamics define?

Solution: There are four laws to thermodynamics

Zeroth law of thermodynamics – If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.

The first law of thermodynamics – Energy can neither be created nor destroyed. It can only change forms. In any process, the total energy of the universe remains the same.

For a thermodynamic cycle, the net heat supplied to the system equals the net work done by the system.

δQ = ΔU + δW

The second law of thermodynamics – The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.

ΔS = ΔQ/T

ΔSTotal = ΔSSystem + ΔSsurrounding

The second law of thermodynamics introduces the concept of entropy.

Third law of thermodynamics – As the temperature approaches absolute zero, the entropy of a system approaches a constant minimum.

ΔST = 0K = 0

QUESTION: 183

Which of the following statements is wrong?

Solution: Knocking in a CI engine occurs because of an ignition lag in the combustion of fuel between the time of injection and the time of actual burning.

As the ignition lag increases, the amount of fuel accumulated in the combustion chamber increases. When combustion actually takes place, an abnormal amount of energy is suddenly released, causing an excessive rate of pressure rise, which results in a knock.

The CI engine knock can be controlled by reducing the delay period. The delay is reduced by the following :

a. High charge temperature

b. High fuel temperature

c. Good turbulence

d. Injection of fuel just before TDC

To decrease the tendency of knock, it is necessary to start the actual burning as early as possible after the injection begins. In other words, it is necessary to decrease the ignition delay and thus decrease the amount of fuel present when the actual burning of the first few droplets starts.

The following are the differences in the knocking phenomenon of the S.I. and C.I. engines:

  • In the S.I engine, the detonation occurs near the end of combustion, whereas in the C.I engine detonation occurs near the beginning of combustion

  • The detonation in the S.I engine is of a homogeneous charge causing a very high rate of pressure rise and very high maximum pressure.

  • In the C.I. engine, the fuel and air are imperfectly mixed, and hence the rate of pressure rise is normally lower than that in the detonating part of the charge in the S.I engine.

  • In the C.I. engine, the fuel is injected into the cylinder only at the end of the compression stroke; there is no question of pre-ignition as in S.I. engine.

  • In the S.I. engine, it is relatively easy to distinguish between knocking and non-knocking operations as the human ear easily finds the distinction.

QUESTION: 184

In a free vortex, velocity

Solution: Free Vortex Flow: When no external torque is required to rotate the fluid mass, that type of flow is called free vortex flow.

The velocity of free vortex flow ∝ 1/r

∴ In a free vortex, velocity decreases with radius.

QUESTION: 185

The working pressure of Cornish boiler is _______ Stirling boiler

Solution: Fire Tube boiler: In this boiler, the hot flue gases are present inside the tubes, and water surrounds them. They are low-pressure boilers. The operating pressure is about 25 bar.

Example to fire tube boilers:

  • Cornish boiler

  • Cochran boiler

  • Locomotive boiler

  • Lancashire boilerScottishh marine boiler

Water Tube Boiler: In this boiler, water is present inside the tubes, and the hot flue gases surround them. They are high-pressure boilers. The operating pressure is about 250 bar.

Examples of water tube boilers:

  • Stirling boiler

  • Babcock and Wilcox boiler

  • Yarrow boiler

  • La mont boiler

  • Loeffler boiler

  • Velox boiler

QUESTION: 186

Angle between the planes of maximum normal stress and minimum normal stress is ________, and angle between planes of maximum shear stress and principal planes is ________ respectively.

Solution: The plane on which normal stress attains its maximum and minimum values are called principal planes. The shear stress on the principal plane is zero.

The planes of maximum and minimum normal stresses are at an angle of 90° to each other.

Planes of maximum stress occur at 45° to the principal planes.