RSMSSB JE Electrical Mock Test - 3 - Electrical Engineering (EE) MCQ

The correct answer is ​Priyanka Meghwal

In News

• Three women from Rajasthan won in the 2024 Lok Sabha elections, two from BJP and one from Congress.

Key Points

• Sanjana Jatav from Congress won in Bharatpur by 51,983 votes, defeating former BJP MP Ramswaroop Koli.
• Manju Sharma from BJP won in Jaipur by 3,31,767 votes.
• Mahima Singh from BJP won in Rajsamand by 3,92,223 votes.
• BJP had fielded five women candidates, out of which two won, and three lost.
• Congress had fielded three women candidates, with one winning and two losing.
• BJP candidates who lost include Priyanka Meghwal from Sriganganagar by 88,153 votes, Indu Devi from Karauli-Dholpur by 98,945 votes, and Jyoti Mirdha from Nagaur by 42,225 votes

The correct answer is Dholpur.Key Points

• Dholpur in Rajasthan boasts of having several wildlife sanctuaries.
• Famous among them is Van Vihar Wildlife Sanctuary which is spread over 60 sq km area, about 18 km from Dholpur in the Bari division.
• Van Vihar was recognized by the government as a wildlife sanctuary way back in 1955.
• The sanctuary extends on the Vindhya Plateau and supports a rather rickety growth of Dhok and Khair (Acacia to cachou) trees.
• Among the easily visible faunal diversity, some of the animals that can be easily spotted here are
  • Sambhar (the great Asian deer)
  • Cheetal (deer spotted)
  • Nilgai (the great Indian antelope)
  • Wild boar
  • Hyena and leopard
• Maharaja Udaibhan Singh of Dholpur had great sympathy for animals and frequented Van Vihar.
• He used to feed not only deer and birds but also foxes and jackals.

Concept:

Dungarpur Railway Station:

• Dungarpur railway station is a small railway station in the Dungarpur district, Rajasthan.
• Its code is DNRP.
• It serves Dungarpur town.
• The station consists of a single platform.
• The platform is not well sheltered.
• It lacks many facilities including water and sanitation.

Explanation:

Ratlam Railway Station:

• Ratlam railway division is one of the six railway divisions under the Western Railway zone of Indian Railways.
• This railway division was formed on 1 April 1952 and its headquarter is located at Ratlam in the state of Madhya Pradesh of India.

Thus, Ratlam is a major railway station, a railway line starting from Dungarpur that will connect the southern part of Rajasthan.

The correct answer is Padmanabha.

Key Points

• Kanhadde Prabandh's text gives information about the struggle between the ruler of Jalore and Alauddin Khilji.
• Kanhadde Prabandh is a book by Indian poet Padmanabha.
• The book tells the story of Raval Kanhadade (Kanhadadeva), the ruler of Jalore.

Additional Information

• It is written in a western Apabhramsha dialect.
• The author was a court-poet of Akhairaja, the king of Visalnagar.
• The work was translated into English by V. S. Bhatnagar.

The correct answer is Begun.

Key Points

• Begun is situated in the Chittorgarh district of Rajasthan.
• Begun farmer's movement was started in 1921.
• It was started for fair implementation of the tax system.
• Farmers decided not to pay taxes and boycott government offices and officials.
• In reaction to it, the government launched an operation to crush the movement.
• Mr Trench opened fire on the peasants which led to the killing of peasants Rupaji and Kripaji.

Additional Information

• Bijolia movement
• Actually, Bijolia was a Jagir class of Udaipur state.
• This movement was started in 1897.
• Most of the peasants belong to Dakan Gotra of the Jats.
• This movement can be divided into 3 phases:-

1. 1897-1915
2. 1915-1923
3. 1923-1941

Important Points

• Bundi movement:
• This movement was started in 1926.
• It was led by Nayanuram Sharma
• These peasants raised their voices against the injustice practices against them.
• This movement is also known as the Barad movement.

The correct answer is 6 years.

Key Points

• Sagarmal Gopa was a great freedom fighter of India.
• He was born on 03 November 1900 in Jaisalmer, Rajasthan in a Brahmin family.
• After the death of his father, he was arrested on 25 May 1941.
• He was arrested on charges of treason and sentenced to rigorous imprisonment of 6 years.

Additional Information

• He was also a part of Gandhiji's non-cooperation movement in 1921 and called on Jaisalmer to be a part of this movement.
• It is believed that he was burnt alive in prison
• He died on 4 April 1946.
• Gopalswaroop Pathak committee was formed to investigate his death.

• The Deccan Lava Plateau is also known as Pathar or Uppermal plateau.
• It is a wide stony upland including the Kota-Bundi plateau section.
• The Chambal along with its tributaries Kali Sindh and Parbati form a triangular alluvial basin of 210m-275m at Kota and mostly black soil found in this region.
• A plateau is a flat, elevated landform that rises sharply above the surrounding area on at least one side.

• Rajasthan is a state in northern India.
• It covers 342,239 square kilometres or 10.4 per cent of India's total geographical area.
• It is the largest Indian state by area and the seventh-largest by population.
• Area: 342,239 km²
• Governor: Kalraj Mishra
• Capital: Jaipur
• Population: 6.89 crores
• Chief minister: Bhajan Lal Sharma (Since 12th Dec 2023)

The correct answer is Ramdevji.

Key Points

• Jambha Jagran Abhiyan was started by Ramdevji.
  • ​To eradicate caste untouchability and discrimination, Ramdev ji started "Jamma Jagran" campaign.
  • He made "Dali Bai" of Meghwal caste his sister.

Additional Information

• Ramdevji
  • In India's Rajasthan and Gujarat, Baba Ramdev is a revered Hindu deity.
  • He is also known by the nicknames 'Ramsa Pir', 'Runicha Ra Dhani', "Baba Ramdev", etc.
  • Hindus consider Ramdev Ji as an incarnation of Krishna and Muslims worship him as 'Ramsa Pir'.
  • He was devoted to uplifting the oppressed and underprivileged and was thought to possess miraculous powers.
  • Pagalve (step symbol) is worshipped as a symbol of Ramdev Ji.
  • The Ramdevra Fair organized in Jaisalmer district.
  • Many devotees attend this Fair to pay homage to Baba Ramdev with ‘Bajans’ and ‘kirtans’ that are chanted during the night.
• Tejaji is a Rajasthani folk god.
  • In rural Rajasthan, he is venerated as a deity and is one of Shiva's principal eleven incarnations.
  • A fair by the name of Mela Tejaji is celebrated every year in Parbatsar, a small village located in District Nagaur.
• Gogaji is a folk diety.
  • ​He is a warrior-hero, venerated as a saint and a 'snake-god'.
  • The main fair of Gogaji is held in Gogamedi (Hanumangarh) while the other fair is held in Sanchore.
• Hadbuji
  • He was born in Nagaur.
  • With the inspiration of his cousin Ramdev Ji, Balinath was made his Guru.
  • He was a good yogi, scholar, and warrior.
  • His temple is in Bengti village (Jodhpur).

The correct answer is A Dinner given by the groom side.

Key Points

• Jannotan in Rajasthani Culture means dinner given by the groom's side.
• The marriages in tribal culture are often different than what we usually see in our day-to-day lives.

Additional Information

• For the Garasia tribe of northwestern Rajasthan, live-in relationships, rather than marriage, are the dominant mode of co-habitation.
• The primitive custom called 'nata pratha' (relationship) among tribal communities in Rajasthan allows men and women to live together without marriage as many times as they want.
  • A man - according to the custom - has to pay money to live with a woman to whom he is not married.
  • The amount is decided by the woman's parents and members of her community.
  • They negotiate a price in thousands of rupees, but the money does not go to the woman who is undergoing 'nata'.

The correct answer is Shri Mahavirji Fair.

Key Points

• Shri Mahavirji Fair
  • A grand fair is held annually in memory of Lord Mahavira from Chaitra Shukla Trayodashi to Vaishakh Krishna Pratipada at Chandangaon (Shri Mahavirji), located on the banks of the Gambhir River in Hindaun Tehsil of Karauli district.
  • This is the largest fair for Jains.
  • According to folklore, a cobbler named Kirpadas used to graze his animals on a mound. Today, this mound is known by his name.
  • Once, his cow did not give milk for several days.
  • To find out the reason, he followed the cow and saw that it was automatically pouring its milk on the mound.
  • Upon digging the mound, he found a beautiful deep red idol.
  • Kirpadas placed the idol in a hut.
  • A Jain named Amarchand Bilala from Baswa was the first to recognize the idol of Mahavirji and donated a large sum to build a temple.
  • Even today, when the fair begins, the first tradition is to have the cobbler's descendants touch the chariot before the Rath Yatra.
  • This Shri Mahavirji Fair is unique in its own way and is an unparalleled event for all religions.

Additional Information

• A fair is held in the month of Shravan on the new moon day for Lord Vishnu's incarnation, King Kalyanji, in Diggi Puri, Malpura Tehsil of Tonk district.
• A grand fair is held from Kartik Shukla Ekadashi to Purnima in Pushkar.
• Jeenmata Fair is held twice a year during the Navratras of Chaitra and Ashwin months.
• The fair of Sheetla Mata is held on Chaitra Krishna Saptami and Ashtami in Sheel ki Doongri village of Chaksu Tehsil in Jaipur district.

The correct answer is On Hands.

Key Points

• ​Ballaya is bangles of ivory and rubber handicraft.
  • These are worn in hands.

Additional Information

• Head Jewellery for Women in Rajasthan-
  • Bor
  • Sir-Maang
  • Seldi
  • Shishphul
  • Tika
• Ear Jewellery for Women in Rajasthan-
  • Bedla
  • Jhukma
  • Kudka
  • Kundal
  • Nasbi
• Neck Jewellery for Women in Rajasthan-
  • Badla
  • Galapatti
  • Haar
  • Hansli

Concept:

Right-hand thumb rule:

• If we hold the current-carrying conductor in the right hand such that the thumb points in the direction of the current, then the fingers encircle the wire will show the direction of magnetic lines of force.

Fleming's left-hand rule:

• When we stretch the forefinger, middle finger, and the thumb of our left hand in such a way that they are mutually perpendicular to each other, if the forefinger indicates the direction of the magnetic field and the middle finger indicates the direction of current, then the thumb will indicate the direction of the force on the conductor.

Fleming's Right -hand rule:

• if we extend the forefinger, middle finger, and the thumb of our right-hand perpendicular to each other as shown in the figure and the thumb pointing towards the conductor's motion and the forefinger pointing towards the magnetic field direction, the middle finger gives us the direction of the induced current flowing in the circuit.

Explanation:

• According to Fleming's left Hand Rule rule, extend the thumb, forefinger, and the middle finger of the left hand in such a way that all the three are mutually perpendicular to each another.
• If the forefinger points in the direction of the magnetic field and the middle finger in the direction of the current, then, the thumb points in the direction of the force exerted on the conductor.
• So, if the current is reversed in the conductor placed in a magnetic field the direction of force is also reversed.

The efficiency of Steam Power Station:

• The overall efficiency of a steam power station is low (about 29%) due mainly given reasons.
• Firstly, a huge amount of heat is lost in the condenser.
• Secondly, heat losses occur at various Stages of the plant.
• We cannot avoid the heat lost in the condenser. It is because heat energy cannot be converted into mechanical energy without temperature difference.
• The greater the temperature difference, the greater is the heat energy converted into mechanical energy.
• Therefore we have to keep the steam in the condenser at the lowest temperature. But the greater temperature difference causes a greater amount of heat lost.
  

Thermal Efficiency: The ratio of heat equivalent of mechanical energy transmitted to the turbine shaft to the heat of combustion of coal is known as thermal efficiency of the steam power station.

The thermal efficiency of a modern steam power station is about 30%.

Overall efficiency: The ratio of heat equivalent of electrical output to the heat of combustion of coal is known as the overall efficiency of the steam power station.

The overall efficiency of the Thermal Power Plant is about 29% because there is an approximation of 1% loss in the Alternator.

The correct answer is option 3):(SCR)

Concept:

• The power semiconductor device is a semiconductor device used as a switch or rectifier in power electronics (for example in a switch-mode power supply). Such a device is also called a power device or, when used in an integrated circuit, a power
• SCR is used where high current and voltage ratings are involved. SCR is used as the load side for control of ac because the negative polarity of the voltage across SCR switched it off easily. Otherwise, a commutation circuit is needed to switch off the device. The typical switching frequency of SCR is 500 Hz

Power semiconductor device features

• Highest switching speed- MOSFET
• Highest voltage / current ratings- SCR
• Easy drive features -MOSFET
• Can be most effectively paralleled- MOSFET
• Can be protected against over-currents with a fuse- SCR
• Gate-turn off capability with regenerative features- GTO
• Easy drive and High power handling capability- SCR

Measurement of power using a dynamometer wattmeter:
In the question, a 3 phase balanced system with balanced load is given,
let's consider the three phases as R, Y, B.
Now an electrodynamometer wattmeter is connected in such a way that, the current coil is connected in series with line Y, and the potential or voltage coil is connected across lines R and B.
So, the current coil measures the current (I_Y) through line Y, and the potential coil measures the line (V_BR) between the lines R and B.

Power measured by wattmeter = W = V_BR × I_Y× cos (angle between V_BR and I_Y)
We can get the phase angle between V_BR and I_Y with help of the phasor diagram shown below

Figure: phasor diagram of 3 phase balanced star connected load

From the above phasor diagram phase angle between V_BR and I_Y is equal to (90°- ϕ)

W = V_BR× I_Y× cos (90° - ϕ)

Given that,
Phase voltage = E and phase current = I
V_BR = √3 × E and I_Y = I
W = √3 E × I cos (90°- ϕ)
= √3 E I sin (ϕ)

Hence, the reading of the wattmeter is directly proportional to E I sin (ϕ).

Note:
We can calculate the reactive power of the 3 phase system just by multiplying the above wattmeter reading with √3.
So, for the measurement of reactive power current coil is connected in one of the phases and then the voltage coil is connected between the remaining phases.

Concept:
The damping ratio symbol is given by ζ and this specifies the frequency response of the 2nd order general differential equation.

Using the damping ratio, one can know the damping level of a system.

We have,

⇒

Characteristics Equation is given by:

1 + G(s) = 0

Comparing with C.E. of the second-order system:

Concept:

Gain Margin (GM): The gain margin of the system can be defined as the value of gain which is to be added to the system, in order to bring the system to the verge of instability.

Gain Margin for an open-loop transfer function is defined by:

Phase cross-over frequency (ω_pc): It is the frequency at which the angle of the open-loop transfer function becomes equal to -180⁰.

Calculation:

The magnitude

For finding ω_pc, the angle of the open-loop transfer function should be equal to -180⁰.

^{∠T(jw) = -180°}

tan^-1(ω_pc) = 60

ω_pc = tan (60⁰)

ω_pc=

|T(jω)|at ω_pc =

|T(jω)| at ω_pc =

GM =

GM = 8

Concept

The effective weight per meter of the conductor is calculated by:

Wmaterial is the weight of the conductor material per meter

Wmaterial = Specific Gravity × Volume of 1 m conductor

W_wind is the wind pressure acting on the conductor per meter

Calculation

Given, A = 2 cm²

Specific Gravity = 9.9 gm/cm3

Wwind = 1.5 kg/m

Wmaterial = 9.9 × 2 × 100 = 1980 gm = 1.98 kg/m

The correct answer is option 1):(Partly demagnetizing and partly cross-magnetizing.)

Concept:

Armature reaction is defined as the effect of armature flux on field flux (ϕm)

Two undesirable effects will be produced on the main field flux by the armature reaction

(1) Decrease in the field flux per pole

(2) Distorted main field flux wave along the air gap.

Based on the power factor the Nature of the armature reaction is

1. Unity Power Factor Load: load is resistive. The nature of the armature reaction is cross magnetizing
2. Leading Power Factor Load: load is capacitive in nature. The nature of armature reaction is partly cross-magnetising and partly demagnetising
3. Lagging Power Factor Load: load is Inductive.The nature of armature reaction is partly cross-magnetising and partly magnetising

• RMS value of the sinusoidal waveform is measured by the average reading voltmeter of which scale is calibrated in terms of rms value.
• Sometimes RMS value of the non-sinusoidal waveform is required to be measured. In that case, the waveform error occurs.
• For such a measurement a true RMS reading voltmeter is required to eliminate the waveform error.

True RMS reading voltmeter:

• True RMS reading voltmeter gives a meter indication by sensing the heating power of waveform which is proportional to the square of the RMS value of the voltage.
• The thermocouple is used to measure the heating power of the input waveform of which heater is sup­plied by the amplified version of the input waveform.
• The output voltage of the thermo­couple is proportional to the square of the RMS value of the input waveform.
• One more thermo-couple, called the balancing thermo-couple, is used in the same thermal environment in order to overcome the difficulty arising out of the non-linear behavior of the thermo-couple.
  

To neglect a voltage source, the terminal across the sources are short-circuited. Because ideally, the internal resistance of the voltage source is zero.

To neglect a current source, the terminal across the sources are open-circuited. Because ideally, the internal resistance of the current source is infinite.

Restriking voltage:

The transient voltage that appears across the contacts of the circuit breaker at the current zero period during arcing is known as Restriking voltage.

The expression for the re-striking voltage is

The maximum value of the re-striking voltage occurs at

The maximum value of re-striking voltage = 2 Vm = 2 × peak value of the system voltage

The rate of rise of re-striking voltage (RRRV)

∴ RRRV = Vm ωn sin ωnt

The rate of rise of re-striking voltage is directly proportional to the natural frequency.

Where L is the inductance of the system

C is the capacitance of the system

So, the rate of rise of re-striking voltage (RRRV) is dependent upon both the inductance and capacitance of the system.

Now, the maximum value of RRRV occurs when ωnt = π/2 i.e. when t = π/2ωn

∴The maximum value of RRRV

RRRV is measured in kV / μ-sec

Classification of buses:

Load Buses:

• In these buses, no generators are connected and hence the generated real power PGi and reactive power QGi are taken as zero.
• The load drawn by these buses is defined by real power -PLi and reactive power -QLi in which the negative sign accommodates for the power flowing out of the bus.
• These buses are sometimes referred to as P-Q bus. The objective of the load flow is to find the bus voltage magnitude |Vi| and its angle δi.

Voltage Controlled Buses:

• These are the buses where generators or voltage-controlled equipments are connected. Therefore the power generation in such buses is controlled through a prime mover while the terminal voltage is controlled through the generator excitation.
• Keeping the input power constant through turbine-governor control and keeping the bus voltage constant using an automatic voltage regulator, we can specify constant PGi and |Vi| for these buses.
• These buses are also referred to as P-V buses. The reactive power supplied by the generator QGi depends on the system configuration and cannot be specified in advance.

Slack or Swing Bus:

• This bus sets the angular reference for all the other buses. Since it is the angle difference between two voltage sources that dictates the real and reactive power flow between them, the particular angle of the slack bus is not important.
• It sets the reference against which angles of all the other bus voltages are measured. For this reason, the angle of this bus is usually chosen as 0°. Furthermore, it is assumed that the magnitude of the voltage of this bus is known.

Important Points:

Bus types for power flow analysis are shown in the table given below:

Where | Vi | = Magnitude of the voltage
δi = Load angle
Pi = Active power
Qi = Reactive power

Concept:

Plug Setting Multiplier (PSM): It is the ratio between the actual fault current in the relay operating coil to pick up current or the relay current setting.

• Plug setting multiplier (PSM) Indicates the severity of the fault.
• The plug setting multiplier is used only in Electromagnetic relays not in numerical relays.
• The operating Times of the Relay operation are depending upon the PSM. The high value of PSM indicates low operating time.

Calculation:

Given that, fault current = 2000 A

current setting = 0.5 × 5 = 2.5

PSM =

= 10

Absolute error (ε):

The difference between the measured value and the true or actual value is called absolute error.

Absolute error ε = A_m - A_t

Where

A_m = measured value

A_t = true or actual value

Gross error:

• Gross errors are the observational errors that happen due to the lack of observation of the observer.
• These errors vary from observer to observer.
• The gross errors may also occur due to improper selection of the instrument.

Relative error:

The relative error is the absolute error over the true or actual value.

Relative static error R.S.E = =

% R.S.E =

Probable error is a quantity formerly used as a measure of variability which is equal to 0.6745 times the standard deviation.

Locus diagram:

The locus diagram is useful for the analysis and designing of the circuit.

Ex: Filters

Current locus diagram:

The single-phase circuit with series R-L is shown below.

R= Resistance

X= Inductive reactance.

the effect of variation in R is shown below

The current locus diagram for the above circuit is shown below.

From the diagram,
Diameter = (V/X)
Radius = (V/2X)
Centre = (0, (V/2X))

Important Points

• When the power factor angle is variable, the shape of the current locus is a semi-circle.
• When the power factor angle is constant, the shape of the current locus is a Straight line.

Concept:

Small signal current gain is defined in common drain amplifier as

For FET, I_g = 0

∴ = Infinite

Ripple Counter

• A ripple counter is an asynchronous counter where only the first flip-flop is clocked by an external clock.
• All subsequent flip-flops are clocked by the output of the preceding flip-flop.
• Asynchronous counters are also called ripple-counters because of the way the clock pulse ripples its way through the flip-flops.
• Only one flip-flop is applied with an external clock pulse and another flip-flop clock is obtained from the output of the previous flip-flop.
• The flip-flop applied with external clock pulse act as LSB (Least Significant Bit) in the counting sequence.
• An n-bit ripple counter can count up to 2n states. It is also known as MOD n counter.

A 3-bit Ripple counter using JK flip-flop –

In the above ripple counter, we can see the external clock is provided only to D₀ FF for D₁ FF, the clock is obtained from Q̅₀ (output of D₀ FF), and for D₂ FF clock pulse is obtained from Q̅₁ (output of D1 FF)

Corona Formation:

• The ionization of air surrounding the high voltage transmission lines causing the conductors to glow, producing a hissing noise, is called Corona Discharge or Corona Effect.
• In transmission lines, conductors are surrounded by the air.
• Air acts as a dielectric medium. When the voltage of air surrounding the conductor exceeds the value of 30kV/cm, the charging current starts to flow through the air, which causes the air to be ionized.
• The ionized air act as a virtual conductor, producing a hissing sound with a luminous violet glow known as the corona.
  

Corona in EHV transmission line:

• Pulseless corona is one of the types of corona discharge that takes place in EHV transmission line conductors.
• The corona current pulses generated by corona discharge are the sources of radio interference from transmission lines.

Concept:

The maximum allowable gate power dissipation (P_gm) is defined as the ratio of average gate power dissipation (P_avg) to the duty cycle (D).

∴ Average gate power dissipation is given by

P_avg = P_gm × D

Calculation:

Given that

P_gm = 15 kW

D = 75% = 0.75

∴ Average gate power dissipation (P_avg) can be calculated as

P_avg = 15 × 0.75

P_avg = 11.25 kW

Additional Information Gate Power Dissipation P_G:

• This rating defines both forward or reverse peak power and the average power applied to the gate.
• If these ratings are exceeded, considerable damage occurs to the gate.
• Therefore, while calculating the voltage and currents applied, the width of gate pulses has to be considered (because the peak power is the function of time).
• For pulse type triggering, gate losses are negligible whereas, in gate signals with a high duty cycle, the gate losses become more significant.
• Other power losses include ON state losses, OFF state losses, forward blocking losses, and reverse blocking losses.
• Turn ON and OFF losses have to be taken into consideration while selecting the SCR rating since these constitute a significant portion of the total losses.
• And also forward and reverse blocking losses are very small compared to the conduction losses since a small leakage current and negligible voltage drop in blocking states.