A.c. Fundamentals, Circuits And Circuit Theory MCQs

Option A: current is maximum

Option B: current is minimum

Option C: impedance is maximum

Option D: voltage across C is minimum

Correct Answer: current is maximum ✔

Option A: apparent power is more than actual power

Option B: reactive power is more than apparent power

Option C: actual power is more than reactive power

Option D: reactive power is more than actual power

Correct Answer: apparent power is more than actual power ✔

Option A: increases with the decrease of capacitance and decrease of resistance

Option B: increases with the decrease of capacitance and increase of resistance

Option C: increases with the increase of capacitance and decrease of resistance

Option D: increase with increase of capacitance and increase of resistance

Correct Answer: increase with increase of capacitance and increase of resistance ✔

Option A: is unaffected by the supply frequency

Option B: decreases with the increase in supply frequency

Option C: increases with the increase in supply frequency

Option D: becomes zero with the increase in supply frequency

Correct Answer: increases with the increase in supply frequency ✔

Option A: actual power is zero

Option B: reactive power is zero

Option C: apparent power is zero

Option D: none of above is zero

Correct Answer: actual power is zero ✔

Option A: increases with increase of inductance and decrease of resistance

Option B: increases with the increase of inductance and the increase of resistance

Option C: increases with the decrease of inductance and decrease of resistance

Option D: increases with decrease of inductance and increase of resistance

Correct Answer: increases with increase of inductance and decrease of resistance ✔

Option A: depends upon the magnitude of R

Option B: depends upon the magnitude of L

Option C: depends upon the magnitude of C

Option D: depends upon the magnitude of R, Land C

Correct Answer: depends upon the magnitude of R ✔

Option A: R only

Option B: L only

Option C: C only

Option D: LorC

Correct Answer: LorC ✔

Option A: R/C

Option B: RC2

Option C: RC

Option D: R2C

Correct Answer: RC ✔

Option A: applied voltage decreases but current increases

Option B: applied voltage increases but current decreases

Option C: both applied voltage and current increase

Option D: both applied voltage and current decrease

Correct Answer: applied voltage decreases but current increases ✔

Option A: Inductance

Option B: Capacitance

Option C: Conductance

Option D: Resistance

Correct Answer: Capacitance ✔

Option A: zero

Option B: lagging

Option C: leading

Option D: unity

Correct Answer: unity ✔

Option A: 25% of maximum value

Option B: 50% of maximum value

Option C: 63% of maximum value

Option D: 90% of the maximum value

Correct Answer: 63% of maximum value ✔

Option A: 4 mA

Option B: 9 mA

Option C: 15 mA

Option D: 25 mA

Correct Answer: 9 mA ✔

Option A: 0.001 s

Option B: 0.1 s

Option C: 10 s

Option D: 100 s

Correct Answer: 0.1 s ✔

Option A: power is consumed in resistance and is equal to I R

Option B: exchange of power takes place between inductor and supply line

Option C: exchange of power takes place between capacitor and supply line

Option D: exchange of power does not take place between resistance and the supply line

Correct Answer: all above are correct ✔

Option A: 42.42 sin 3141

Option B: 60 sin 25 t

Option C: 30 sin 50 t

Option D: 84.84 sin 25 t

Correct Answer: 42.42 sin 3141 ✔

Option A: A coil with large resistance

Option B: A coil with low resistance

Option C: A coil with large distributed capacitance

Option D: A coil with low distributed capacitance

Correct Answer: A coil with large distributed capacitance ✔

Option A: low efficiency

Option B: high power factor

Option C: unity power factor

Option D: maximum load current

Correct Answer: high power factor ✔

Option A: 12 kW

Option B: 22 kW

Option C: 32 kW

Option D: 64 kW

Correct Answer: 32 kW ✔

Option A: the big size of the inductor

Option B: the reactance of the inductor

Option C: the current flowing in the inductor

Option D: the statement given is false

Correct Answer: the statement given is false ✔

Option A: iron loss in core

Option B: skin effect

Option C: increase in temperature

Option D: capacitive effect between adjacent coil turns

Correct Answer: iron loss in core ✔

Option A: demand

Option B: load

Option C: power

Option D: form

Correct Answer: power ✔

Option A: 4 kVAR

Option B: 6 kVAR

Option C: 8 kVAR

Option D: 16 kVAR

Correct Answer: 6 kVAR ✔

Option A: have a high voltage developed across each inductive and capacitive section

Option B: have a high impedance

Option C: act like a resistor of low value

Option D: have current in each section equal to the line current

Correct Answer: have a high impedance ✔

Option A: reduce eddy current loss

Option B: increase heat radiation

Option C: make assembly cheap and easier

Option D: reduce circuit permeability

Correct Answer: reduce eddy current loss ✔

Option A: ratio of net reactance and impedance

Option B: ratio of kW and kVA

Option C: ratio of J and Z

Option D: ratio of W and VA

Correct Answer: ratio of net reactance and impedance ✔

Option A: current

Option B: voltage

Option C: power

Option D: frequency

Correct Answer: voltage ✔

Option A: create more electrical noise

Option B: are likely to melt under excessive eddy current heat

Option C: consume more power

Option D: exhibit unwanted inductive and capacitive effects

Correct Answer: exhibit unwanted inductive and capacitive effects ✔

Option A: can dissipate considerable amount of power

Option B: can act as energy storage devices

Option C: connecting them in parallel in¬creases the total value

Option D: oppose sudden changes in voltage

Correct Answer: can dissipate considerable amount of power ✔

Option A: a line which represents the magnitude and phase of an alternating quantity

Option B: a line representing the magnitude and direction of an alternating quantity

Option C: a coloured tag or band for distinction between different phases of a 3-phase supply

Option D: an instrument used for measuring phases of an unbalanced 3-phase load

Correct Answer: a line which represents the magnitude and phase of an alternating quantity ✔

Option A: reactive power in a circuit

Option B: the extent of neutralisation of reactive power in a circuit

Option C: a purely capacitive circuit’s ability to pass current

Option D: a purely capacitive circuit’s ability to resist the flow of current

Correct Answer: a purely capacitive circuit’s ability to pass current ✔

Option A: 0°

Option B: 45°

Option C: 90°

Option D: 180°

Correct Answer: 0° ✔

Option A: lags

Option B: leads

Option C: remains in phase with

Option D: none of the above

Correct Answer: leads ✔

Option A: The current through each element is same

Option B: The voltage across element is in proportion to it’s resistance value

Option C: The equivalent resistance is greater than any one of the resistors

Option D: The current through any one element is less than the source current

Correct Answer: The current through any one element is less than the source current ✔

Option A: between 0° and 90°

Option B: between 90° and 180°

Option C: between 180° and 270°

Option D: no where

Correct Answer: no where ✔

Option A: resistance only

Option B: inductance only

Option C: capacitance only

Option D: none of the above

Correct Answer: resistance only ✔

Option A: very low

Option B: low

Option C: medium

Option D: high

Correct Answer: high ✔

Option A: electronic equipment

Option B: transformers

Option C: current transformers

Option D: auto transformers

Correct Answer: electronic equipment ✔

Option A: low

Option B: very low

Option C: high

Option D: very high

Correct Answer: high ✔

Option A: resistive

Option B: inductive

Option C: capacitive

Option D: none of the above

Correct Answer: capacitive ✔

Option A: 200 Hz

Option B: 100 Hz

Option C: 60 Hz

Option D: 50 Hz

Correct Answer: 50 Hz ✔

Option A: high voltage across the load

Option B: low voltage across the load

Option C: unequal line voltages across the load

Option D: minimun voltage across the load

Correct Answer: unequal line voltages across the load ✔

Option A: 282.8 V

Option B: 141.4 V

Option C: 111 V

Option D: 100 V

Correct Answer: 282.8 V ✔

Option A: Square wave

Option B: Sine wave

Option C: Half wave rectified sine wave

Option D: Triangular wave

Correct Answer: Half wave rectified sine wave ✔

Option A: increasing core length

Option B: decreasing the number of turns

Option C: decreasing the diameter of the former

Option D: choosing core material having high relative permeability

Correct Answer: choosing core material having high relative permeability ✔

Option A: Vc and VR

Option B: VL and VR

Option C: Vc and VL

Option D: none of the above

Correct Answer: Vc and VL ✔

Option A: 0.5 of peak value

Option B: 0.707 of peak value

Option C: same as peak value

Option D: zero

Correct Answer: 0.707 of peak value ✔

Option A: series resistance needs a low-resistance source for sharp rise in current

Option B: series resonance needs a high-resistance source for sharp increase in current

Option C: parallel resonance needs a low-resistance source for a sharp in¬crease in impedance

Option D: parallel resonance needs a low-resistance source for a sharp rise in line current

Correct Answer: series resistance needs a low-resistance source for sharp rise in current ✔

Option A: the speed with which the alternator runs

Option B: the number of cycles generated in one minute

Option C: the number of waves passing through a point in one second

Option D: the number of electrons passing through a point in one second

Correct Answer: the number of waves passing through a point in one second ✔

Option A: inductive reactance

Option B: capacitive reactance

Option C: resistance

Option D: capacitance

Correct Answer: capacitance ✔

Option A: 60 sin 25 t

Option B: 60 sin 50 t

Option C: 84.84 sin 3141

Option D: 42.42 sin 314 t

Correct Answer: 84.84 sin 3141 ✔

Option A: less than unity

Option B: unity

Option C: greater than unity

Option D: zero

Correct Answer: unity ✔

Option A: be reduced by half

Option B: be doubled

Option C: be four times as high

Option D: be reduced to one fourth

Correct Answer: be doubled ✔

Option A: be reduced by half

Option B: be doubled

Option C: be four times at high

Option D: be reduced to one fourth

Correct Answer: be reduced by half ✔

Option A: the current through the resistance is more

Option B: the current through the resistance is less

Option C: both resistance and inductance carry equal currents

Option D: none of the above

Correct Answer: both resistance and inductance carry equal currents ✔

Option A: true power

Option B: reactive power

Option C: volt-amperes

Option D: instantaneous power

Correct Answer: true power ✔

Option A: the capacitive reactance in ohms

Option B: the current flowing in capacitor

Option C: the size of the capacitor being quite big

Option D: the statement is incorrect

Correct Answer: the statement is incorrect ✔

Option A: apparent power

Option B: true power

Option C: reactive power

Option D: none of the above

Correct Answer: true power ✔

Option A: 220 V

Option B: 220V3V

Option C: 220/V3 V

Option D: none of the above

Correct Answer: 220 V ✔

Option A: zero

Option B: 0.08 lagging

Option C: 0.8 leading

Option D: unity

Correct Answer: unity ✔

Option A: the current is in phase with the voltage

Option B: the current lags behind the voltage by 90°

Option C: the current leads the voltage by 90°

Option D: the current can lead or lag by 90°

Correct Answer: the current lags behind the voltage by 90° ✔

Option A: unsymmetrical part of the wave form

Option B: the quarter cycle

Option C: the half cycle

Option D: the whole cycle

Correct Answer: the whole cycle ✔

Option A: changes in the stored energy in the inductors and capacitors

Option B: impedance of the circuit

Option C: applied voltage to the circuit

Option D: resistance of the circuit

Correct Answer: A. changes in the stored energy in the inductors and capacitor ✔

Option A: current lags behind the voltage by 90°

Option B: current leads the voltage by 90°

Option C: current can lead or lag the voltage by 90°

Option D: current is in phase with the voltage

Correct Answer: current is in phase with the voltage ✔

Option A: C only

Option B: L only

Option C: R only

Option D: all above

Correct Answer: R only ✔

Option A: the more heat than produced by A.C. when flowing through the same circuit

Option B: the same heat as produced by A.C. when flowing through the same circuit

Option C: the less heat than produced by A.C. flowing through the same circuit

Option D: none of the above

Correct Answer: B. the same heat as produced by A.C. when flowing through the same circuit ✔

Option A: falls to 36.8% of its final steady value

Option B: rises to 38.6% of its final steady value

Option C: rises to 63.2% of its final steady value

Option D: none of the above

Correct Answer: rises to 63.2% of its final steady value ✔

Option A: r.m.s. value is equal to average value

Option B: r.m.s. value of current is greater than average value

Option C: r.m.s. value of current is less than average value

Option D: none of the above

Correct Answer: r.m.s. value is equal to average value ✔

Option A: oscillating

Option B: square wave

Option C: sinusoidal

Option D: non-oscillating

Correct Answer: sinusoidal ✔

Option A: to reduce line losses

Option B: to maximise the utilization of the capacities of generators, lines and transformers

Option C: to reduce voltage regulation of the line

Option D: due to all above reasons

Correct Answer: due to all above reasons ✔

Option A: resistance

Option B: inductance

Option C: capacitance

Option D: both B. and C.

Correct Answer: D. both B. and C. ✔

Option A: consumes some power on average

Option B: does not take power at all from a line

Option C: takes power from the line during some part of the cycle and then returns back to it during other part of the cycle

Option D: none of the above

Correct Answer: takes power from the line during some part of the cycle and then returns back to it during other part of the cycle ✔

Option A: directly as the cross-sectional area of magnetic core

Option B: directly as square of number of turns

Option C: directly as the permeability of the core

Option D: inversely as the length of the iron path

Correct Answer: E. as A. to (d) ✔

Option A: apparent power is equal to the actual power

Option B: reactive power is more than the apparent power

Option C: reactive power is more than the actual power

Option D: actual power is more than its reactive power

Correct Answer: reactive power is more than the actual power ✔

Option A: only at the time of turning off

Option B: only at the time of turning on

Option C: at the time of turning on and off

Option D: at all the time of operation

Correct Answer: ✔

Option A: will change the maximum value of current at resonance

Option B: will change the resonance frequency

Option C: will change the impedance at resonance frequency

Option D: will increase the selectivity of the circuit

Correct Answer: will increase the selectivity of the circuit ✔

Option A: reduces load handling capability of electrical system

Option B: results in more power losses in the electrical system

Option C: overloads alternators, transformers and distribution lines

Option D: results in more voltage drop in the line

Correct Answer: results in all above ✔

Option A: increases with increase of inductance and decrease of resistance

Option B: increases with the increase of inductance and the increase of resistance

Option C: increases with decrease of inductance and decrease of resistance

Option D: increases with decrease of inductance and increase of resistance

Correct Answer: increases with increase of inductance and decrease of resistance ✔

Option A: capacitance is less and frequency of supply is less

Option B: capacitance is less and frequency of supply is more

Option C: capacitance is more and frequency of supply is less

Option D: capacitance is more and frequency of supply is more

Correct Answer: capacitance is less and frequency of supply is less ✔

Option A: 0.05 s

Option B: 0.005 s

Option C: 0.0005 s

Option D: 0.5 s

Correct Answer: 0.005 s ✔

Option A: kW

Option B: kVA

Option C: kV

Option D: kVAR

Correct Answer: kVA ✔

Option A: 90

Option B: 60

Option C: 45

Option D: 30

Correct Answer: 45 ✔

Option A: average value/r.m.s. value

Option B: average value/peak value

Option C: r.m.s. value/average value

Option D: r.m.s. value/peak value

Correct Answer: r.m.s. value/average value ✔

Option A: 0.636 Emax

Option B: 0.707 Emax

Option C: 0.434 EWc

Option D: lAUEmax

Correct Answer: 0.636 Emax ✔

Option A: 0.5 Imax

Option B: 0.707

Option C: 0.9

Option D: 1.414 Lmax

Correct Answer: 0.707 ✔

Option A: 1.414

Option B: 0.707

Option C: 1.11

Option D: 0.637

Correct Answer: 1.11 ✔

Option A: triangular wave

Option B: sine wave

Option C: square wave

Option D: half wave rectified sine wave

Correct Answer: square wave ✔

Option A: half wave rectified sine wave

Option B: triangular wave

Option C: sine wave

Option D: square wave

Correct Answer: half wave rectified sine wave ✔

Option A: 180″

Option B: 90°

Option C: 60°

Option D: 0°

Correct Answer: 90° ✔

Option A: 360°

Option B: 180°

Option C: 90°

Option D: 0°

Correct Answer: 180° ✔

Option A: both will reach their minimum values at the same instant

Option B: both will reach their maximum values at the same instant

Option C: when one wave reaches its maxi¬mum value, the other will reach its minimum value

Option D: none of the above

Correct Answer: when one wave reaches its maxi¬mum value, the other will reach its minimum value ✔

Option A: average voltage

Option B: r.m.s. voltage

Option C: peak voltage

Option D: none of the above

Correct Answer: r.m.s. voltage ✔

Option A: mean value

Option B: r.m.s. value

Option C: peak value

Option D: average value

Correct Answer: mean value ✔

Option A: a sinusoid of the same frequency

Option B: a sinusoid of half the original frequency

Option C: a sinusoid of double the frequency

Option D: not a sinusoid

Correct Answer: a sinusoid of the same frequency ✔

Option A: 2.5

Option B: 5

Option C: 10

Option D: 15

Correct Answer: 10 ✔

Option A: the same as frequency

Option B: time required to complete one cycle

Option C: expressed in amperes

Option D: none of the above

Correct Answer: time required to complete one cycle ✔

Option A: peak value to r.m.s. value

Option B: r.m.s. value to average value

Option C: average value to r.m.s. value

Option D: none of the above

Correct Answer: r.m.s. value to average value ✔

Option A: 100 n

Option B: 50 jt

Option C: 25 JT

Option D: 5 n

Correct Answer: 100 n ✔

Option A: purely inductive circuit

Option B: R-L circuit

Option C: R-C circuit

Option D: R-L-C circuit

Correct Answer: R-L-C circuit ✔