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# Test: Mechanical Engineering-1

## 100 Questions MCQ Test Mock Test Series for SSC JE Mechanical Engineering | Test: Mechanical Engineering-1

Description
This mock test of Test: Mechanical Engineering-1 for Mechanical Engineering helps you for every Mechanical Engineering entrance exam. This contains 100 Multiple Choice Questions for Mechanical Engineering Test: Mechanical Engineering-1 (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Mechanical Engineering-1 quiz give you a good mix of easy questions and tough questions. Mechanical Engineering students definitely take this Test: Mechanical Engineering-1 exercise for a better result in the exam. You can find other Test: Mechanical Engineering-1 extra questions, long questions & short questions for Mechanical Engineering on EduRev as well by searching above.
QUESTION: 1

### An ideal gas at 27ºC is heated at constant pressure till its volume becomes three times. What would be then the temperature of gas?

Solution:

T1 = 27 +273 =300 K

V1 =V

V2=3V

T2 =?

use  P1V1/T1  = P2V2/T2

GIVEN P1 =P2

SO V1/T1 =V2/T2

V/300 = 3V/T2

T2 =900K

= 627°C

QUESTION: 2

### Measurement of temperature is based on which law of thermo dynamics?

Solution:

Law of thermodynamics is the basis for measurement of temperature and setting its scale. In simple word, Zeroth law of thermodynamics says that “When two bodies are separately in thermal equilibrium with the third body, then the two are also in thermal equilibrium with each other.”

QUESTION: 3

### Hot coffee stored in a well insulated thermos flask is an example of

Solution:

As the hot coffee remains hot for a long time so neither heat nor mass is exchanged with the surroundings and hence it is an example of isolated system.

QUESTION: 4

Which one of the following expresses the reversible work done by the system (steady flow)
between states 1 and 2?

Solution:
QUESTION: 5

A closed system receives 60 kJ heat but its internal energy decreases by 30 kJ. Then the work done by the system is

Solution:

Qsupplied = 60KJ

du= -30 KJ

from first law of thermo=

dQ = du + dW

60 = -30 + dW

dW = 90 KJ

QUESTION: 6

Work transfer between the system and the surroundings

Solution:

The work is the path function so the work transfer between the system and the surrounding depend on the path that followed by tha system.

QUESTION: 7

The value of for an irreversible cycle is

Solution:
QUESTION: 8

One Joule (J) is equal to

Solution:

1 joule (J) = 1.00 newton meters (N-m)

QUESTION: 9

The temperature at which the volume of a gas becomes zero is called

Solution:

General gas equation

pv=mrt

at absolute zero kelvin temp.
pressure =zero

that means

0×v= mr×0

therefore volume will be zero at absolute zero kelvin temp.

QUESTION: 10

The molecular mass expressed in gram (i.e. 1 gmole) of all gases, at N. T. P., occupies a volume of

Solution:

According to Avogadro's law ,the volume of a gram mole of all gases at the pressure of 760 mm of Hg and temperature of 0 degree centigrade is same and is equal to 22.4 litres.

QUESTION: 11

The sum of internal energy (U) and the product of pressure and volume (p.v) is known as

Solution:

dU + PdV = dH which is enthalpy

QUESTION: 12

Carnot cycle has maximum efficiency for

Solution:

No engine working between two given temperatures can be more efficient than a reversible engine working between the same two temperatures and that all the reversible engines working between the same two temperatures have the same efficiency, whatever the working substance may be.

QUESTION: 13

A refrigeration system

Solution:
QUESTION: 14

The C.O.P. of a refrigerator working on a reversed Carnot cycle is where
T1 = Lowest absolute temperature, and
T2 = Highest absolute temperature

Solution:
QUESTION: 15

The leakage in a refrigeration system using freon is detected by

Solution:

The leaks in a refrigeration system using Freon are detected by Halide torch which on detection produces greenish flame lighting

QUESTION: 16

The COP of a heat pump βhp and the COP of a refrigerator βRef are related as

Solution:
QUESTION: 17

In electrolux refrigerator

Solution:

The hydrogen passes across the surface of the ammonia. It lowers the ammonia vapor pressure enough to allow the liquid ammonia to evaporate. The evaporation of the ammonia extracts heat from the evaporator. This, in turn, extracts heat from the food storage space, lowering the temperature inside the refrigerator.

QUESTION: 18

The correct sequence of the given four cycles on T-s plane in figure 1, 2, 3, 4 is

(1) (2) (3) (4) Solution:
QUESTION: 19

An Otto cycle has a compression ratio of 8. If 250 kJ of work is extracted from the cycle, the heat rejected by the cycle is

Solution: QUESTION: 20

The two reference fuels used for cetane rating are

Solution:

Cetane and alpha-methyl naphthalene are the reference fuels taken for cetane rating.

QUESTION: 21

The stoichiometric air-fuel ratio for petrol is 15 :1. What is the air-fuel ratio regarded for maximum power ?

Solution:

For maximum power, slightly rich mixture is required in order to burn more fuel and get energy.

QUESTION: 22

Match List-I (SI Engine Operating Mode) with List –II (Appromimate A/F Ratio) and select the correct answer using the code given below the lists Solution:
QUESTION: 23

A spark plug gap is kept from

Solution:

spark plug gap is kept from- 0.3-0.7 mm because 0.3-0.7 is perfect gap for making spark in spark plug.

QUESTION: 24

The ignition quality of petrol is expressed by

Solution:

Ignition quality of petrol is expressed by octane number and that of diesel by cetane number.

QUESTION: 25

Which of the following is not a boiler mounting?

Solution:

Economizer is boiler accessory and others are mounting

QUESTION: 26

The function of a safety valve is

Solution:
QUESTION: 27

An air preheater is installed

Solution:
QUESTION: 28

Match List-I (Type of boiler) with List-II (Classification of boiler) select the correct answer
using the codes given below the lists: Solution:
QUESTION: 29

Benson boiler is one of the high pressure boilers having

Solution:
QUESTION: 30

The draught in locomotive boilers is produced by

Solution:
QUESTION: 31

The function of economizer in a boiler is to

Solution:

Boiler Economiser ( Sometimes Called Economizer ) is the Energy improving device that helps to reduce the cost of operation by saving the fuel. In boilers, economizers are generally Heat Exchangers which are designed to exchange heat with the fluid, generally water.

QUESTION: 32

The critical pressure ratio for maximum discharge through a nozzle is given by

Solution:
QUESTION: 33

Surging basically implies

Solution:

Surging is caused due to unsteady, periodic and reversal of flow through the compressor when the compressor has to operate at less mass flow rate than a predetermined value

QUESTION: 34

Phenomenon of chocking in compressor means

Solution:

Choking is the condition which occurs in the compressor in which it operates at very high mass flow rate and flow through the compressor can't be further increased as mach number at some part of the compressor reach to unity i.e. to sonic velocity and the flow is said to be choked.

QUESTION: 35

The instantaneous centre of rotation of a rigid thin disc rolling on a plane rigid surface is located at

Solution:
QUESTION: 36

A four-bar chain has

Solution:
QUESTION: 37

Which one of thefollowing conversions is used by a lawn-sprinkler which is a four barme chanisms?

Solution:
QUESTION: 38

Which one of the following drives is used for a constant velocity ratio, positive drive with large centre distance between the driver and driven shafts?

Solution:
QUESTION: 39

The number of degrees of freedom of an epicyclic gear train is

Solution:

Two Cases
1 DOF - when the sun is constant and planet is roatating as well as revolving around sun and arm rotating.
2 DOF - when sun and arm are rotating and planet is rotating as well as revolving around sun.

QUESTION: 40

In which one of the following is a fly wheel generally employed?

Solution:
QUESTION: 41

The motion between a pair when limited to a definite direction, irrespective of the direction of force, applied, is known as

Solution:

Completely constrained motion is a type of constrained motion in which relative motion between the links of a kinematic pair occurs in a definite direction by itself, irrespective of the external forces applied.

QUESTION: 42

Which of the following is an example of a higher pair?

Solution:
QUESTION: 43

The relation between number of pairs (P) forming a kinematic chain and the number of links (l)

Solution:
QUESTION: 44

The design calculations for members subject to fluctuating loads with the same factor of safety yield the most conservative estimates when using

Solution:
QUESTION: 45

When a nut is tightened by placing a washer below it the bolt will be subjected to

Solution:
QUESTION: 46

In a fillet welded joint, the weakest area of the weld is

Solution:
QUESTION: 47

18/8 steel contains

Solution:

18/8 stainless steel is nominally 18% chromium and 8% nickel, with the remainder being mainly iron; it does however also contain other elements, but at very low levels. It is also known as 302 or 304 grade stainless steel.

QUESTION: 48

An aluminium member is designed on the basis of

Solution:
QUESTION: 49

Guest's theory is used for

Solution:

MAXIMUM SHEAR STRESS THEORY (GUEST's or TRESCA's THEORY)

According to this theory, the elastic failure occurs when the greatest shear stress reaches a value equal to the shear stress at elastic limit in a simple tension test. This is used for ductile material

QUESTION: 50

The notch sensitivity q is expressed in terms of fatigue stress concentration factor Kf and theoretical stress concentration factor Kv as

Solution:
QUESTION: 51

The dimensions of surface tension are

Solution:

surface tension is often expressed as an amount of force exerted in the surface perpendicular to a line of unit length. The unit then is newtons per metre, which is equivalent to joules per square metre.

QUESTION: 52

If the surface tension of water air interface is 0.073 N/m, the gauge pressure inside a rain drop
of 1 mm diameter will be

Solution: QUESTION: 53

When can a piezometer be not used for pressure measurement in pipes?

Solution:
QUESTION: 54

Three immiscible liquids of specific densities ρ , 2ρ and 3ρ are kept in a jar. The height of the liquids in the jar and at the piezo meter fitted to the bottom of the jar are as shown in the figure below. The ratio H/h is.

Solution: QUESTION: 55

The critical value of Reynolds number for transition from laminar to turbulent boundary layer in external flows is taken as

Solution:

For flow over a flat plate, transition from laminar to turbulent boundary layer occurs when Reynolds number at x exceeds Rex,crit ~ 500,000. Transition may occur earlier, but it is dependent especially on the surface roughness.

QUESTION: 56

The head loss in turbulent flow in pipe varies

Solution:
QUESTION: 57

Laminar flow between closely spaced parallel plates is governed by the consideration of which one of the following pair of forces?

Solution:
QUESTION: 58

A centrifugal pump gives maximum efficiency when its blades are

Solution:

The efficiency of a centrifugal pump will be maximum when the blades are bent backward.

QUESTION: 59

A manometer is used to measure

Solution:
QUESTION: 60

When a body is placed over a liquid, it will float if

Solution:

Gravitational force i.e. weight should be less than the upthrust force for a body to float

QUESTION: 61

The discharge through a large rectangular orifice is given by

where H1= Height of the liquid above the top of the orifice,
H2= Height of the liquid abvoe the bottom of the orifice,
b = Breadth of the orifice, and
Cd= Coefficient of discharge

Solution:
QUESTION: 62

The coefficient of viscosity may be determined by

Solution:
QUESTION: 63

The unit discharge through the turbine is

Solution:
QUESTION: 64

The deformation of a bar under its own weight as compared to that when subjected to a direct axial load equal to its own weight will be

Solution:

Actually the deformation under a conectrated load P at end will give deformation equals to PL/AE.

The deformation due to self weight is is give by PL/2AE.

QUESTION: 65

What is the relationship between the linear elastic properties; Young's modulus (E), rigidity modulus
(G) and bulk modulus (K)?

Solution: QUESTION: 66

Which one of the following mohr's circles represents the state of pure shear?

Solution:

For pure shear, radius is equal to shear stress and the centre lies on the point of intersection of axes.

QUESTION: 67

Auto frettage is the method of

Solution: QUESTION: 68

A simply supported beam is loaded as shown in the figure below. The maximum shear force in the beam will be

Solution: QUESTION: 69

The ratio of the compressive critical load for a long column fixed at both the ends and a column with one end fixed and the other end free is

Solution: QUESTION: 70

A short column of external diameter D and internal diameter d carries an eccentric load W.
The greatest eccentricity which the load can be applied without producing tension on the crosssection of the column would be

Solution: QUESTION: 71

The Poisson's ratio for cast iron varies from

Solution:
QUESTION: 72

The relation between Young's modulus (E), shear modulus (C) and bulk modulus (K) is given by

Solution:
QUESTION: 73

The point of contraflexure occurs in

Solution:
QUESTION: 74

The slenderness ratio is the ratio of

Solution:
QUESTION: 75

Fatigue test is carried out for

Solution:
QUESTION: 76

According to lami's theorem

Solution:
QUESTION: 77

A couple produces

Solution:

A couple in mechanics refers to two equal forces that act in opposite direction . The resultant force in a couple is zero, but it does have a moment of force(torque).A couple produces rotational motion in the object it is acting.

QUESTION: 78

The ratio of static friction to dynamic friction is always

Solution:

The static friction is always greater than the dynamic friction and hence the ratio of a bigger number to a smaller number is more than 1

QUESTION: 79

A framed structure as shown fig. is a Solution:

A framed structure is perfect, if the number of members are equal to ( 2 n- 3) , where n is the no. of joints. In this figure, there are 3 joints ,therefore, (2*3-3) = 3
That means there are three members , so it is a perfect frame.

QUESTION: 80

Eutectoid reaction occurs at

Solution:

In eutectoid reaction, the austenite transforms into a phase mixture of ferrite (containing 0.76% C) and cementite. This phase mixture is known as pearlite. The eutectoid reaction occurs at a constant temperature. This is known as eutectoid temperature and is 723oC

QUESTION: 81

Addition of magnesium to cast iron increases its

Solution:

Magnesium is a powerful inoculant in cast iron. When added in concentrations exceeding 0.04%, it produces a spheroidal form of graphite that improves the iron's strength and ductility. Magnesium is an abundant metal with a price roughly comparable to that of aluminum, albeit usually higher

QUESTION: 82

Consider the following quenching media:
1. Oil
2. Water
3. WaterNaOH
4. Brine

The correct sequence of these media in order of increasing hardness of steel ounder going heat
treatment is

Solution:
QUESTION: 83

Gunmetal, which is used in journal bearings, contains

Solution:
QUESTION: 84

A sand casting mould assembly is shown in the given figure. The elements marked A and B are respectively Solution:
QUESTION: 85

The process of removing the burrs of flash from a forged component in drop forging is called

Solution:

Trimming is a manufacturing process that is used as a finishing operation for forged parts, in order to remove flash. Flash is a characteristic common in most metal forgings. For that reason trimming, while not technically a forging or even a forming operation in general, is discussed in this section. Trimming basically presses a part through a cutting die that runs the periphery of the work. The cutting die are precisely designed to remove the flash from a particular part. Most often it is desirable to perform this operation while the work is still hot for maximum efficiency, therefore it is usually incorporated into the larger production process. For more delicate forgings, flash can be ground or cut off using different methods. For certain metal forgings, this is an extremely quick and easy method for the removal of the extra material.

QUESTION: 86

Which one of the following processes is the wire drawing process?

Solution:
QUESTION: 87

High speed electron beam of electron beam welding is focused on the weld spot using

Solution:
QUESTION: 88

The ratio between Oxygen and Acetylene gases for neutral flame in gas welding is

Solution:

The neutral flame has a one-to-one ratio of acetylene and oxygen. It obtains additional oxygen from the air and provides complete combustion. It is generally preferred for welding. The neutral flame has a clear, well-defined, or luminous cone indicating that combustion is complete

QUESTION: 89

The instrument or device used to measure the cutting forces in machings is

Solution:
QUESTION: 90

Which of the following property is desirable in parts subjected to shock and impact loads?

Solution:
QUESTION: 91

Wrought iron

Solution:
QUESTION: 92

18 - 4 - 1 high speed steel contains

Solution:
QUESTION: 93

The type of tool used on lathe, shaper and planer is

Solution:
QUESTION: 94

Flank wear occurs mainly on the

Solution:
QUESTION: 95

Cutting fluids are used to

Solution:
QUESTION: 96

The tool life is said to be over if

Solution:
QUESTION: 97

A mandrel is used to hold

Solution:

Mandrel is used to hold a hollow bar or a bar with a bore wen turning between live centre and dead cente of a lathe. A moving mandrel is also used for tube drawing

QUESTION: 98

In a planer

Solution:

On the planer the work is moved against a stationary tool: on the shaper the tool moves across the work, which is stationary. On the planer the tool is fed into the work; on the shaper the work is usually fed across the tool. The drive on the planer table is either by gears or by hydraulic means.

QUESTION: 99

Surface grinding is done to produce

Solution:

Surface grinding is used to produce a smooth finish on flat surfaces. It is a widely used abrasive machining process in which a spinning wheel covered in rough particles (grinding wheel) cuts chips of metallic or nonmetallic substance from a workpiece, making a face of it flat or smooth.

QUESTION: 100

A simply supported beam 'A' of length l, breadth b and depth d carries a central load W. Another beam 'B' of the same dimensions carries a central load equal to 2 W. The deflection of beam 'B' will be __________ as that of beam 'A'.

Solution: