ACPC

Q1.The arc voltage in a circuit breaker is

1. in phase with the arc current
2. leading the arc current by 90°
3. lagging the arc current by 90°
4. lagging the arc current by 45°

Correct Ans: A

Q2.It is difficult to interrupt a capacitive current because

1. The current has a leading power
2. The restriking voltage can be high
3. Current magnitude is very small
4. Stored energy in the capacitor is very high

Correct Ans: B

Q4.If the positive, negative and zero sequence reactances of an element of a power system are 0.2, 0.2 and 0.6 pu respectively, then the element would be a

1. Synchronous generator
2. Static load
3. Synchronous motor
4. Transmission line

Correct Ans: D

Q6.\(Y_{bus}\) used in power flow studies and \(Z_{bus}\) used in short circuit studies

1. are the same
2. are transpose of each other
3. are inverse of each other
4. have no interrelation

Correct Ans: C

Q8.A d.c series motor develops a torque of 30 N-m at 3 A load current. If the current is increased to 6 A, the torque developed will be

1. 30 N-m
2. 120 N-m
3. 60 N-m
4. 90 N-m

Correct Ans: B

Q9.If the air gap in an induction motor is increased,

1. The power factor will decrease.
2. The magnetiziing current of the rotor will decrease.
3. The motor speed will increase.
4. The windage losses will increase.

Correct Ans: A

Q10.If the value of the shunt field resistance of a shunt generator is greater than the critical resistance, the generator will

1. Excite to full voltage.
2. Fail to excite.
3. Excite to half of the full voltage.
4. Excite to one fourth of the full voltage.

Correct Ans: B

Q11.Five cells are connected in series in a row and then four such rows are connected in parallel to feed current to a resistive load of 1.25 \(\Omega\). Each cell has
an emf of 1.5 V with internal resistance of 0.2 \(\Omega\). The current through the load will be

1. 5A
2. 2.5A
3. 10A
4. 2A

Correct Ans: A

Q12.Bundle conductors are used in transmission lines, the effective capacitance and inductance will respectively

1. Decrease and increase
2. Increase and decrease
3. Remain same and increase
4. Decrease and remain same

Correct Ans: B

Q13.Resistance switching is used in air blast circuit breakers to

1. Reduce the magnitude of fault current
2. Control the circuit breaker operating time
3. Damp out the fast transient
4. Change the fault current power factor

Correct Ans: C

Q14.A trasformer at full load has a copper loss of 400 W and an iron loss of 200 W. The copper loss and iron loss at half full load will respectively be

1. 100 W and 200 W
2. 200 W and 200 W
3. 200 W and 100 W
4. 400 W and 400 W

Correct Ans: A

Q15.The operating time of the back-up relay should be more than

1. The primary relay time
2. The primary fault clearing time
3. The critical clearing time
4. The pick up time

Correct Ans: A

Q16.In a squirrel cage rotor, the bars are not placed parallel to the shaft but are skewed to have

1. Greater mechanical strength
2. less rotor losses
3. Uniform torque
4. High efficiency

Correct Ans: C

Q18.For a 12 bus system, with 3 voltage controlled buses, the size of Jacobian matrix is

1. 11 × 11
2. 12 × 12
3. 24 × 24
4. 19 × 19

Correct Ans: D

Q19.When load on a transformer is increased, the eddy current

1. Is increased.
2. Remains unchanged.
3. Is decreased.
4. Becomes zero.

Correct Ans: B

Q20.A power station supplies a peak load of 50 MW, 40 MW and 70 MW to three localities. The annual load factor is 0.5 pu and the diversity factor of the load at the station is 1.55, the maximum demand on the station and the average load respectively will be

1. 120 and 60.8 MW
2. 90 and 50.6 MW
3. 103.2 and 51.61 MW
4. 100 and 0.51 MW

Correct Ans: C

Q21.The following sequence currents were recorded in a power system under a fault condition: \(I_{positive} = j1.653 \: p.u. , I_{negative} = -j0.5 \: p.u. \: and \: I_{zero} = -j 1.153 \: p.u.\). The fault is

1. Single line to ground
2. Three phase
3. Double line to ground
4. Line to line

Correct Ans: C

Q22.An RLC series circuit is predominantly inductive

1. At resonant frequency
2. Above resonance frequency
3. Below resonance frequency.
4. At lower half power frequency.

Correct Ans: B

Q23.A change of 5% in the supply voltage to an induction motor will produce a change of approximately

1. 5% in the rotor torque.
2. 10% in the rotor torque.
3. 20% in the rotor torque.
4. 25% in the rotor torque.

Correct Ans: B

Q24.To limit current chopping in vacuum circuit breakers, the contact material employed should have the properties of

1. Low conductivity and high vapour pressure.
2. Low conductivity and low vapour pressure.
3. High conductivity and high vapour pressure.
4. High conductivity and low vapour pressure.

Correct Ans: A

Q25.The surge impedance of a 400 km long overhead transmission line is 400 ohms. For a 200 km length of the same line, the surge impedance will be

1. 100 ohm
2. 400 ohm
3. 800 ohm
4. 200 ohm

Correct Ans: B

Q26.The motor used where high starting torque is required and where the load is subject to heavy fluctuations is a

1. d.c. series motor
2. Differential compound motor
3. d.c. shunt motor
4. Cumulative compound motor

Correct Ans: D

Q28.Four identical alternators each rated for 20 MVA, 11 kV having a subtransient reactance of 16% are working in parallel. The short circuit level at the bus bars is

1. 500 MVA
2. 200 MVA
3. 1000 MVA
4. 750 MVA

Correct Ans: A

Q29.In an interconnected grid system, the more efficient plants are used as

1. Peak load plants
2. Base load plants
3. Both base and peak load plants
4. Standby plants

Correct Ans: B

Q30.The in-rush current in a transformer at no load is maximum if the supply voltage is switched on at

1. Peak voltage value
2. Half peak voltage value
3. Zero voltage value
4. 0.866 times peak voltage value

Correct Ans: C

Q33.A 100 V source has a series internal resistance of 1\(\Omega\). The maximum power that can be delivered to the load is

1. 1000 W
2. 2000 W
3. 2500 W
4. 5000 W

Correct Ans: C

Q34.The open loop transfer function of a unity feedback control system is \(G(s)\) = \(\frac{1}{(s + 2)^2}\). The closed loop transfer function will have poles at

1. -2, -2
2. -4, -1
3. -2, ±j
4. -2, 2

Correct Ans: C

Q35.In a d.c. generator, the main function of the compensating winding is to

1. Assist in commutation
2. Eliminate reactance voltage
3. Reduce the demagnetizing effect of armature reaction
4. Reduce the distorting effect of armature reaction

Correct Ans: C

Q36.The earth transformer is used to

1. Avoid harmonics in the transformer
2. Provide artificial neutral earthing where the neutral point is not accessible
3. Improve stability of the system
4. Measure the voltage

Correct Ans: B

Q37.The mechanical power developed by a d.c. motor is maximum when the back e.m.f is

1. Equal to half of the applied voltage
2. Equal to the applied voltage
3. Equal to one third of the applied voltage
4. Equal to one fourth of the applied voltage

Correct Ans: A

Q38.The bus-bar zone faults are generally

1. phase-to-phase faults.
2. single-line-to-ground faults
3. double line-to-ground faults
4. 3-phase short-circuits

Correct Ans: B

Q39.For a given number of poles and armature conductors, a lap winding will carry

1. More current than a wave winding
2. Less current than a wave winding
3. Same current as a wave winding
4. No current

Correct Ans: A

Q40.Shunt compensation in EHV lines is used to

1. Reduce the fault level
2. Improve the voltage profile
3. Improve stability
4. Improve the efficiency

Correct Ans: B

Q42.A 240 V d.c. series motor takes 40 A when giving its rated output at 1500 rpm. Its resistance is 0.3 ohm. What resistance must be added to obtain the rated torque at starting?

1. 2.4 Ω
2. 1.9 Ω
3. 3.2 Ω
4. 5.7 Ω

Correct Ans: D

Q43.On the two sides of a star-delta transformer

1. Voltages and currents are in phase
2. Voltages and currents differ in phase by 30°
3. Voltages differ in phase by 30°, but currents are in phase
4. Currents differ in phase by 30°, but voltages are in phase

Correct Ans: B

Q46.The steady state stability of the power system can be improved by

1. using machines of high impedance
2. connecting transmission lines in series
3. connecting lines in parallel
4. reducing the excitation of the machines.

Correct Ans: C

Q47.Which of the following plants is almost inevitably used as a base load plant?

1. Diesel engine plant
2. Gas turbine plant
3. Nuclear power plant
4. Pumped storage plant

Correct Ans: C

Q48.The induced voltages on the transmission lines due to electrostatic and electromagnetic induction is reduced by

1. Ferranti effect
2. Corona effect
3. Bundling of conductors
4. Transposition of conductors.

Correct Ans: D

Q49.By which of the following factors is the sag of the transmission line least affected?

1. Current through the conductor
2. Self weight of the conductor
3. Ice deposited on the conductor
4. Temperature of the surrounding air

Correct Ans: A

Q50.The reserve generating capacity of a plant which is not in operation but can be made available for service is the

1. Firm power
2. Hot reserve
3. Cold reserve
4. Spinning reserve

Correct Ans: C

Q52.In over current protection, the setting of the earth fault relay is

1. More than the phase fault relay
2. Less than the phase fault relay
3. Equal to that of the phase fault relay
4. Zero

Correct Ans: B

Q53.The insulation resistance of a cable of length 10 km is 1 MΩ. For a cable of length 200 km, the insulation resistance will be

1. 0.05 MΩ
2. 0.1 MΩ
3. 0.5 MΩ
4. 20 MΩ

Correct Ans: A

Q54.Compared to the breaking capacity of circuit breaker its making capacity should normally be

1. More
2. Equal
3. Less
4. The two are unrelated to each other

Correct Ans: A

Q55.In a thyristor, the rate of rise of the anode current at the time of turn-on can be kept below specified limits by

1. Using a small inductor in series with the anode circuit
2. Using a small inductor in parallel with the anode circuit
3. Using a small capacitor in parallel with the anode circuit
4. Using a small capacitor series with the anode circuit

Correct Ans: A

Q57.100% string efficiency means :

1. Self capacitance is zero
2. Self capacitance is maximum
3. Shunt capacitance is zero
4. Shunt capacitance is maximum

Correct Ans: C

Q58.An over current relay, having a plug setting of 75 % is connected to the supply circuit through a current transformer of ratio 200/5. The pick-up value of the current is

1. 5 A
2. 2.5 A
3. 6.25 A
4. 3.75A

Correct Ans: D

Q59.Biot Savart law states that

1. The magnetic flux density at a point due to a current element is normal to the plane containing the element and the line joining the element and the point.
2. The magnetic flux density at a point due to a current element is in phase with the plane containing the element and the line joining the element and the point.
3. The magnetic flux density at a point due to a current element is at 45° to the plane containing the element and the line joining the element and the point.
4. The magnetic flux density at a point due to a current element is in phase opposition to the plane containing the element and the line joining the element and the point.

Correct Ans: A

Q60.Which of the following is not a characteristic of an ideal Op amp?

1. The open loop voltage gain is negatively infinite
2. The open loop voltage gain is zero
3. The input impedance is infinitely large
4. The output impedance is zero

Correct Ans: B

Q61.Directional over-current relay is used for protection of

1. long transmission line
2. large power transformer.
3. ring main distribution line.
4. radial distribution line.

Correct Ans: C

Q62.If the inductance and capacitance of a system are 1 H and 0.01 μF respectively and the instantaneous value of the current interrupted is 10 A, the value of the shunt resistance across the breaker for critical damping is

1. 5 kΩ
2. 50 kΩ
3. 10 kΩ
4. 80 kΩ

Correct Ans: A

Q63.For a two port symmetrical bilateral network, if the transmission parameters A=3 and B=1 \(\Omega\), the value of parameter C is

1. 3 \(\Omega\)
2. 9 \(\Omega\)
3. 8 \(\Omega\)
4. 6 \(\Omega\)

Correct Ans: C

Q64.Which semiconductor power device out of the following is not a current triggered device?

1. Thyristor
2. G.T.O.
3. Triac
4. MOSFET

Correct Ans: D

Q66.A power system has two generating plants and the power is being dispatched economically with \(P_1 =125 MW \: and \: P_2 =250 MW.\) The loss coefficients are:

\(B_{11} =0.10 \times 10^{-2} MW^{-1}\) ,

\(B_{12} = -0.01 \times 10^{-2} MW^{-1}\),

\(B_{22} =0.13 \times 10^{-2} MW^{-1}\).

To raise the total load on the system by \(1 \: MW\), there will be an additional cost of \(Rs. 200 \: per \: hour\). The penalty factor for the plant \(1\) will be

1. 1.5
2. 1.4
3. 1.25
4. 1.6

Correct Ans: C

Q67.The relay that is best suited for phase fault relaying for medium transmission lines is

1. Admittance relay
2. Impedance relay
3. Directional relay
4. Reactance relay

Correct Ans: B

Q68.Circuit turn-off time of an SCR is defined as the time

1. Taken by the SCR to turn off
2. Required for the SCR current to become zero
3. For which the SCR is reverse biased by the commutation circuit
4. For which the SCR is reverse biased to reduce its current below the holding current

Correct Ans: C

Q70.In the measurement of power by two wattmeter method, when the readings of the two wattmeters are equal and opposite, it can be concluded that the power factor is

1. Zero
2. Unity
3. Lagging
4. Leading

Correct Ans: A

Q71.The unit protection scheme provides

1. Primary protection
2. Remote protection
3. Back up protection
4. Simultaneous protection

Correct Ans: A

Q72.The inertia constant H of a machine of 200 MVA is 2 pu. Its value corresponding to 400 MVA will be

1. 2 pu
2. 1 pu
3. 4 pu
4. 10 pu

Correct Ans: B

Q74.The presence of earth wire in case of overhead lines

1. Increases the line capacitance
2. Decreases the line capacitance
3. Increases the line inductance
4. Decreases the line inductance

Correct Ans: A

Q76.The boundary of a protective system is decided by the location of

1. Circuit breakers
2. Transformers
3. Current transformers
4. Generators

Correct Ans: C

Q77.Capacitive Voltage Transformer (CVT) is used to

1. Reduce losses in a transmission line.
2. Reduce the incidence of overvoltage surges on transmission lines.
3. Improve the power factor of transmission.
4. Connect instruments on the LT side

Correct Ans: D

Q78.If a \(75 MVA, 10 kV\) synchronous generator has \(X_d =0.4 \: pu\), then \(X_d\) value in \(p.u.\) to a base of \(100 MVA, 11 kV\) is

1. 0.4 pu
2. 0.2 pu
3. 0.44 pu
4. 0.52 pu

Correct Ans: C

Q80.In a thyristor, the holding current is

1. More than the latching current
2. Equal to the latching current
3. Less than the latching current
4. Zero

Correct Ans: C

Q89.If \( \phi =x^2yz^3 \) and \( \bar{F} = xz \bar{i} - y^2 \bar{j} + 2x^2 \bar{k} \) then what is the value of \( curl(\phi \bar{F})\)

1. \( (2xy^4+3x^2y^3z) \bar{i} - (4x^3yz+8xy^2z^3) \bar{j} - (2xyz^3+x^3z^4) \bar{k} \)
2. \((2x^4z^3 + 3x^2y^3z^2)\bar{i} + (4x^3yz^3 - 8x^3yz^3)\bar{j} - (2xy^3z^3 + x^3z^4)\bar{k} \)
3. \( (2xyz+3yz) \bar{i} + (4xyz+3x^2y^2z^3) \bar{j} - (2xyz^3+x^3z^4) \bar{k} \)
4. None of these

Correct Ans: B

Q1.In thermal power plants, the pressure in the working fluid cycle is developed by

1. feed water pump
2. superheater
3. condenser
4. turbine

Correct Ans: A

Q2.A triangular wave can be generated by

1. Integrating a square wave
2. Differentiating a square wave
3. Integrating a sine wave
4. Differentiating a sine wave

Correct Ans: A

Q3.Tesla coils is a__________transformer

1. Core less
2. Cascaded
3. Low impedance
4. high frequency resonant

Correct Ans: D

Q4.To increase the transmission capability of a high voltage long line

1. The resistance can be increased
2. The resistance can be decreased
3. The series reactance can be reduced
4. The shunt admittance can be reduced

Correct Ans: C

Q5.For Nyquist plot we use

1. Open loop function
2. Closed loop function
3. Characteristic equation
4. None of the above

Correct Ans: A

Q6.The voltage of a bus can be controlled by controlling the

1. Phase angle
2. Reactive power of the bus
3. Active power of the bus
4. Phase angle and reactive power

Correct Ans: B

Q7.In case of a split-phase motor, the phase shift between currents in the two windings is around

1. \(30^\circ\)
2. \(70^\circ\)
3. \(90^\circ\)
4. \(120^\circ\)

Correct Ans: A

Q8.The transmission line distance protection relay having the property of being inherently directional is

1. Impedance relay
2. MHO relay
3. OHM relay
4. Reactance relay

Correct Ans: B

Q9.During hunting of synchronous motor

1. Negative phase sequence currents are generated
2. Harmonics are developed in the armature circuit
3. Damper bar develops torque
4. Field excitation increases

Correct Ans: C

Q10.Skewing is used in induction motors in order to reduce torque due to

1. Time harmonics
2. Slot harmonics
3. Space harmonics
4. Reverse rotating fields

Correct Ans: B

Q11.A synchronous motor operating with normal excitation adjusts to increased load due to increase in

1. Back emf
2. Power factor
3. Armature current
4. Non of the above

Correct Ans: C

Q12.Isolators used in transmission lines are capable of breaking

1. fault current
2. no current
3. charging current
4. load current

Correct Ans: C

Q13.The torque-speed characteristic of a Repulsion motor resembles with which of the following d.c. motor characteristic?

1. Series
2. Separately excited
3. Shunt
4. Compound

Correct Ans: A

Q14.A synchronous generator connected to an infinite bus is overexcited. Considering only the reactive power from the point of the system the machine acts as

1. A capacitor
2. An inductor
3. A resistor
4. None of these

Correct Ans: A

Q15.A D.C machine has maximum efficiency near

1. Half-full load
2. Full-load
3. Twice the Full-load
4. No load

Correct Ans: B

Q16.In the formation of Routh-Hurwitz array for a polynomial, all the elements of a row have zero values, this premature termination of the array indicates the presence of

1. Only one root at origin
2. Only positive real root
3. Only negative real root
4. Imaginary roots

Correct Ans: D

Q17.Creep error is associated with which one of the following meters

1. Moving iron meter
2. Energy meter
3. Electrodynamo meter
4. Watt meter

Correct Ans: B

Q18.Which of the following instruments is most accurate

1. PMMC
2. Moving iron
3. Thermocouple
4. Induction type

Correct Ans: A

Q19.The energy stored in the magnetic field of solenoid 30 cm long and 3 cm diameter wound with 1000 turns of wire carrying current of 10 A is

1. 0.015 J
2. 0.5 J
3. 0.15 J
4. 1.15 J

Correct Ans: C

Q20.A major advantage of active filter is that they can be realized without using

1. Op-amps
2. Resistors
3. Inductor
4. Capacitors

Correct Ans: C

Q21.The function of interpoles in a DC machine is to

1. Reduce field winding heating
2. Improve commutation
3. Compensate for air gap variation
4. Reduce losses

Correct Ans: B

Q22.When the supply voltage to an induction motor is reduced by 10%, the maximum torque will decrease by approximately

1. 5%
2. 10%
3. 20%
4. 40%

Correct Ans: C

Q23.The rms value of the resultant current in a wire which carries a dc current of 10 A and a sinusoidal alternating current peak value 20 A is

1. 17.32 A
2. 14.10 A
3. 22.40 A
4. 30.00 A

Correct Ans: A

Q24.The P-N junction diode is a

1. Passive device
2. Vacuum tube
3. Unilateral device
4. Bilateral device

Correct Ans: C

Q25.Swamping resistance is used to compensate error due to

1. Stray magnetic field
2. Temperature variation
3. Large supply variations
4. None of the above

Correct Ans: B

Q26.Buchholz relay is used for protection in case of a

1. transformer
2. Synchronous generator
3. Bus-bar
4. Induction motor

Correct Ans: A

Q27.By burden of the relay, we generally mean

1. volt-ampere rating of relay.
2. current rating of relay.
3. voltage rating of relay.
4. watt rating of relay.

Correct Ans: A

Q28.Constant voltage source is

1. Active and bilateral
2. Passive and bilateral
3. Active and unilateral
4. Passive and unilateral

Correct Ans: C

Q29.Feedback control systems are

1. Band pass filters
2. Low pass filters
3. High pass filters
4. None of the above

Correct Ans: B

Q30.The resistance of a reverse biased ideal diode is

1. Zero
2. Infinity
3. Low
4. Negative

Correct Ans: B

Q31.A gas turbine works on

1. Carnot cycle
2. Brayton cycle
3. Dual cycle
4. Rankine cycle

Correct Ans: B

Q32.The inductive reactance of a transformer depends on

1. Electromotive force
2. Magnetomotive force
3. Magnetic flux
4. Leakage flux

Correct Ans: D

Q33.Latching current of an SCR is

1. Below 10%
2. 10-20%
3. 20-25%
4. 25-30%

Correct Ans: A

Q34.Demand factor on a power system is

1. Greater than unity
2. Always less than unity
3. Normally greater than unity
4. Always unity

Correct Ans: B

Q35.A transformer can have zero regulation at

1. Zero pf.
2. Unity pf.
3. Lagging pf.
4. Leading pf.

Correct Ans: D

Q36.Induction wattmeter can be used to measure

1. ac power
2. dc power
3. ac and dc power
4. None of these

Correct Ans: A

Q37.In which transformer, the tertiary winding is used?

1. Star-delta
2. Delta-delta
3. Star-star
4. Delta-star

Correct Ans: C

Q38.Transistor is a

1. Current controlled current device
2. Current controlled voltage device
3. Voltage controlled current device
4. Voltage controlled voltage device

Correct Ans: A

Q39.In two wattmeter method of power measurement, one of the wattmeters will show negative reading when the load power factor angle is strictly

1. Greater than \(60^\circ\)
2. Less than \(60^\circ\)
3. Greater than \(30^\circ\)
4. Less than \(30^\circ\)

Correct Ans: A

Q40.The magnetic shielding of the operating parts in an electrical instrument is achieved by using

1. Glass cover
2. Iron case
3. Brass case
4. Anti magnetic material

Correct Ans: B

Q41.For both lap and wave windings, there are as many commutator bars as the number of

1. Armature conductors
2. Winding elements
3. Poles
4. Slots

Correct Ans: B

Q42.The speed-time curve for urban services has no

1. Coasting period
2. Braking period
3. Free running period
4. Acceleration period

Correct Ans: C

Q43.The common collector amplifier has the highest

1. Voltage gain
2. Current gain
3. Power gain
4. Output impedance

Correct Ans: B

Q44.The magnetizing current in a transformer is rich in

1. \(3^{rd}\) harmonics
2. \(5^{th}\) harmonics
3. \(7^{th}\) harmonics
4. \(13^{th}\) harmonics

Correct Ans: A

Q45.The resistance of a reverse biased ideal diode is

1. Zero
2. Low
3. Negative
4. Infinity

Correct Ans: D

Q46.An increase in number of poles of an induction motor results in

1. Decrease in maximum pf
2. Increase in maximum pf
3. No change in maximum pf
4. Cannot be predicted

Correct Ans: A

Q47.Critical voltage limit of a transmission line is increased by

1. Increasing the radius of conductor
2. Increasing the spacing between conductors
3. Reducing the spacing between conductors
4. Reducing the radius of the conductors

Correct Ans: A

Q48.The electric braking system commonly employed in rolling mills, elevators and printing presses is

1. Regenerative
2. Rheostatic
3. Dynamic
4. Plugging

Correct Ans: D

Q49.Diversity factor in a power system is

1. Always less than unity
2. Normally less than unity
3. Always more than unity
4. Normally more than unity

Correct Ans: C

Q50.The DC motor that draws almost same power at different loads is

1. Cumulative compound
2. Differential compound
3. Shunt
4. Series

Correct Ans: D

Q51.The insulation level of 400 kV EHV overhead transmission line is decided on the basis of

1. Lightning overvoltage
2. Switching overvoltage
3. Corona inception voltage
4. Radio and TV interference

Correct Ans: B

Q52.A series R-L-C circuit will have unity power factor if operated at a frequency of

1. \(\frac{1}{LC}\)
2. \(\frac{1}{\omega\sqrt LC}\)
3. \(\frac{1}{\omega^2 LC}\)
4. \(\frac{1}{2\pi\sqrt LC}\)

Correct Ans: D

Q53.Power transformer is generally designed to give maximum efficiency at

1. Full load
2. Half load
3. No load
4. None of above

Correct Ans: A

Q54.A DC generator beyond critical resistance will generate

1. Maximum power
2. Maximum voltage
3. Maximum current
4. No voltage

Correct Ans: D

Q55.The flux in transformer core

1. Increase with load
2. Decrease with load
3. Remains constant irrespective of load
4. None of the load

Correct Ans: C

Q56.In a microprocessor,the address of the next instruction to be executed is stored in

1. Stack pointer
2. Address latch
3. Program counter
4. General purpose resister

Correct Ans: C

Q57.The cascade intermediate stages should be

1. CB
2. CE
3. CC
4. CE and CB

Correct Ans: B

Q58.Without a dc source, a clipper acts like it a

1. Clamper
2. Chopper
3. Rectifier
4. Demodulator

Correct Ans: C

Q59.The best method of bias is

1. Base resistor method
2. Potential divider method
3. Collector to base bias
4. Base bias with collector and emitter feedbacks

Correct Ans: B

Q60.In an R-C coupled amplifier the voltage gain

1. Constant over range of frequency
2. Always increasing with frequency
3. Always decreasing with frequency
4. None of these

Correct Ans: A

Q61.A power transformer is a constant_______device

1. Current
2. Voltage
3. Main flux
4. Power

Correct Ans: C

Q62.The current flowing through armature conductors of dc motor is

1. pulsating
2. ac
3. dc
4. None of these

Correct Ans: B

Q63.In an induction motor if the air gap is increased

1. Speed will reduce
2. Breakdown torque will reduce
3. Efficiency will improve
4. Power factor will be lowered

Correct Ans: D

Q64.Graphite is used in Nuclear power station as

1. Fuel
2. Coolant
3. Moderator
4. Electrode

Correct Ans: C

Q65.The advantage of neutral earthing is

1. safety of personnel.
2. reduction of earth fault current.
3. elimination of arcing fault current.
4. none of the above.

Correct Ans: C

Q66.Thermo-couple is based on

1. Joule's
2. Thomson
3. Seeback effect
4. None of these

Correct Ans: C

Q67.Open-circuit test in a transformer is performed with

1. Rated transformer voltage
2. Rated transformer current
3. Direct current
4. High frequency supply

Correct Ans: A

Q68.After completion of the execution micro processor returns to

1. An execute state
2. A fetch state
3. An interrupt state
4. An Halt state

Correct Ans: B

Q69.The no-load current in a transformer lags the applied voltage by

1. \(90^\circ\)
2. \(0^\circ\)
3. \(75^\circ\)
4. About \(115^\circ\)

Correct Ans: C

Q70.When an alternator connected to an infinite busbar is shutdown, the busbar voltage will

1. Increase
2. Decrease
3. Remain unchanged
4. Unpredictable

Correct Ans: C

Q71.A motor used for punching machine is usually subjected to

1. Full load continuously
2. Part of full load continuously
3. No-load
4. Intermittent load

Correct Ans: D

Q72.The most inappropriate among the disadvantages of Gauss-Seidel method of load flow solution is

1. Slow conversion
2. Unreliable conversion
3. A good initial guess is essential for convergence
4. Choice of slack bus affects convergence

Correct Ans: C

Q73.Which semiconductor device acts like a diode and two transistors?

1. SCR
2. UJT
3. Triac
4. Diac

Correct Ans: B

Q74.Under voltage relays are mostly used for

1. Transformer protection
2. Bus-bar protection
3. Motor protection
4. Feeder protection

Correct Ans: C

Q75.N-Type semi-conductor the doping material is

1. A trivalent material
2. A pentavalent material
3. A tetravalent material
4. germanium

Correct Ans: B

Q76.The temperature coefficient of an intrinsic semiconductor is

1. Zero
2. Positive
3. Negative
4. Like that of metals

Correct Ans: C

Q77.Reactance relay is normally preferred for protection against

1. Earth faults
2. Phase faults
3. Open circuit faults
4. None of the above

Correct Ans: A

Q78.A negative sequence relay is commonly use to protect

1. An alternator
2. A transformer
3. A transmission line
4. A bus bar

Correct Ans: A

Q79.The speed of a universal motor can be controlled by

1. Introducing a variable resistance series with the motor
2. Tapping the speed at various points
3. Centrifugal mechanism
4. All of the above

Correct Ans: D

Q80.Higher synchronous reactance is preferred in the present-day alternator because one can have

1. Reduced sub-transient current
2. Reduce harmonic current
3. Reduce transient currents
4. Higher voltage regulation with load

Correct Ans: C

Q81.If P(A)=0.07 then, what is the probability of "Not A"?

1. 0.3
2. 0.03
3. 0.33
4. 0.93

Correct Ans: D

Q82.A card is drawn from the pack of 52 cards. Find the probability of getting an Ace.

1. \(\frac{1}{13}\)
2. \(\frac{1}{26}\)
3. \(\frac{1}{52}\)
4. \(\frac{1}{53}\)

Correct Ans: A

Q83.If 'p' is the probability of success, 'q' is the probability of failure and 'n' is the number of trials in a Binomial distribution then, what is the standard deviation?

1. \(\sqrt {np}\)
2. \(\sqrt {npq}\)
3. \((npq)\)
4. \((npq)^2\)

Correct Ans: B

Q84.To solve the equation \(f(x) = 0\) using Bisection method, we set a search interval \([a, b]\) such that

1. \(f(a) . f(b) < 0\)
2. \(f(a) . f(b) > 0\)
3. \(f(a) . f(b) = 0\)
4. None of the above

Correct Ans: A

Q85.At least one Eigen value of a Singular matrix____________.

1. -1
2. 0
3. 1
4. None of the above

Correct Ans: B

Q86.The argument of a complex number \(\frac{1+i}{1-i}\) is,________

1. \(-\pi\)
2. \(-\frac{\pi}{2}\)
3. \(\frac{\pi}{2}\)
4. \(\pi\)

Correct Ans: C

Q87.The values of \(x\) for which function \(f(x)=\frac{x^2-3x+4}{x^2-3x-4}\) does not exists.

1. 4, -1
2. -4, 1
3. 4, 1
4. -4, -1

Correct Ans: A

Q88.The solution of \(x\frac{dy}{dx}+y=x^4\) with condition \(y(1)=\frac{6}{5}\) is _________

1. \(y=\frac{4x^4}{5}+\frac{4}{5x}\)
2. \(y=\frac{x^4}{5}+\frac{1}{x}\)
3. \(y=\frac{x^4}{5}+1\)
4. \(y=\frac{x^5}{5}+1\)

Correct Ans: B

Q89.Which one of the following is true for the relationship between three vectors \(i + j + 2k\), \(2i + j + k\) and \(i + 2j +k\)?

1. The vectors are mutually perpendicular
2. The vectors are linearly dependent
3. The vectors are parallel
4. The vectors are linearly independent

Correct Ans: D

Q90.Evaluate the integral \(\int_{1}^{3}\frac{1}{x}dx\) is using trapezoidal rule with step size 1. The value of the integral is ________

1. 1
2. 1.08
3. 1.16
4. 1.24

Correct Ans: C

Q91.Laplace Transform of the function \(e^{2t} \sin 3t\) is________.

1. \(\frac{3}{s^2+4s+13}\)
2. \(\frac{3}{s^2+4s-5}\)
3. \(\frac{3}{s^2-4s-5}\)
4. \(\frac{3}{s^2-4s+13}\)

Correct Ans: D

Q92.The inverse Laplace transform of \(\log(\frac{s+b}{s+a})\) is __________.

1. \(\frac{e^{-at}-e^{-bt}}{t}\)
2. \(\frac{e^{-at}+e^{-bt}}{t}\)
3. \(\frac{e^{at}-e^{bt}}{t}\)
4. \(\frac{e^{at}+e^{bt}}{t}\)

Correct Ans: A

Q93.The solution of the differential equation \(x^2D^2y+xDy=0\) is________.

1. \(y=c_1+c_2 \log x\)
2. \(y=c_1+c_2 e^x\)
3. \(y=c_1+c_2 \log z\)
4. None of these

Correct Ans: A

Q94.The function \(f(x)=2x^3+3x^2-12x+7\) is decreasing in_________.

1. [1,3]
2. R-[-2,1]
3. [0,2]
4. [- 2, 1]

Correct Ans: D

Q95.The improper integral \(\int_{0}^{\infty}\frac{dx}{x^2+4}\)

1. Diverges to \(\infty\)
2. Diverges to \(-\infty\)
3. Converges to \(\frac{\pi}{4}\)
4. Converges to \(\frac{1}{4}\)

Correct Ans: C

Q96.If errors of 3% in E and -2% in R are made, then the percentage error in \(P=\frac{E^2}{R}\) is___________.

1. 0%
2. 4%
3. 6%
4. 8%

Correct Ans: D

Q97.Which of the following statements are true in general?
Statement 1: Singular matrix is always a square matrix.

Statement 2: Every square matrix is symmetric matrix.

Statement 3: Every square matrix satisfies its own characteristic equation.

1. Only statement 1
2. Statement 1 and 2
3. Statement 1 and 3
4. All of above

Correct Ans: C

Q98.Poisson distribution is applied for_________

1. Continuous random variable
2. Discrete random variable
3. Uncertain random variable
4. None of these

Correct Ans: B

Q99.Which of the following method is used to find solution of Ordinary Differential Equation?

1. Bisection Method
2. Newton Raphson method
3. Euler's method
4. Successive approximation method

Correct Ans: C

Q100.Function of two variables \(f(x, y)\) has Maxima at point (a, b) if_____

1. \(rt-s^2<0\) and \(r<0\)
2. \(rt-s^2>0\) and \(r<0\)
3. \(rt-s^2>0\) and \(r>0\)
4. None of these

Correct Ans: B