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MCQOPTIONS
This section includes 785 Mcqs, each offering curated multiple-choice questions to sharpen your Electronic Devices Circuits knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
An AC source is applied to a pure inductive circuit. What is the active power consumed by the circuit? |
| A. | V * I |
| B. | 0 |
| C. | \(\frac{{{V^2}}}{{{X_L}}}\) |
| D. | \(\frac{1}{2}L{I^2}\) |
| Answer» C. \(\frac{{{V^2}}}{{{X_L}}}\) | |
| 152. |
Power consumed in a series RLC circuit can be calculated using: |
| A. | P = VI cosφ |
| B. | P = VI |
| C. | P = IR |
| D. | P = IR cos φ |
| Answer» B. P = VI | |
| 153. |
A power factor of 1.0 indicates: |
| A. | purely inductive circuit |
| B. | purely capacitive circuit |
| C. | purely resistive circuit |
| D. | purely reactive circuit |
| Answer» D. purely reactive circuit | |
| 154. |
A 4 Ω resistor is connected in series with a 10 mH inductor, across a 100 V, 50 Hz voltage source. The impedance of the circuit will be |
| A. | 5 – j 3.14 |
| B. | 5 + j 3.14 |
| C. | 4 – j 3.14 |
| D. | 4 + j 3.14 |
| Answer» E. | |
| 155. |
A sinusoidal AC voltage has peak value 220 V. What is the RMS value? |
| A. | 220√2 |
| B. | 110√2 |
| C. | 110 |
| D. | None of the above |
| Answer» C. 110 | |
| 156. |
Determine the value of reactive power (in VAR) of a circuit having power factor of 0.6, when the apparent power of the circuit is 50 VA. |
| A. | 20 |
| B. | 40 |
| C. | 60 |
| D. | 80 |
| Answer» C. 60 | |
| 157. |
If R, Y, and B are called as the supply line, then the potential difference between any two lines is known as the ________ voltage |
| A. | Line |
| B. | Phase |
| C. | Peak |
| D. | Peak to peak |
| Answer» B. Phase | |
| 158. |
A sinusoidal voltage of v(t) = 100 cos (377t) is applied to a nonlinear load, resulting in a current which is expressed in Fourier series from as i(t) = 8 + 15 cos (377t + 30°) + 6 cos[2(377)t + 60°] Effective value of the current is: |
| A. | 10 A |
| B. | 14 A |
| C. | 16 A |
| D. | 12 A |
| Answer» C. 16 A | |
| 159. |
A complex voltage wave consisting of a fundamental and third harmonic component is applied to a pure capacitor. The reactance offered by the capacitor to the third harmonic component voltage as compared to the fundamental component voltage is: |
| A. | the same |
| B. | double |
| C. | triple |
| D. | one-third |
| Answer» E. | |
| 160. |
Find the rms current in a capacitor of 0.1 μF, when an AC voltage of 5 V and frequency of 5 kHz is applied to it. |
| A. | 1.57 mA |
| B. | 15.71 mA |
| C. | 12.57 mA |
| D. | 25.32 mA |
| Answer» C. 12.57 mA | |
| 161. |
Consider a parallel RLC circuit having inductance of 10 mH, Capacitance of 100 μF. Determine the value of resistance that would lead to a critically damped response? |
| A. | 5 Ω |
| B. | 10 Ω |
| C. | 20 Ω |
| D. | 15 Ω |
| Answer» B. 10 Ω | |
| 162. |
An AC current is expressed as i = 50 sin 100 t A. What is the half-cycle average value of that current? |
| A. | \( \frac{{50}}{\pi } ~A\) |
| B. | 50 A |
| C. | 100 A |
| D. | \( \frac{{100}}{\pi } ~A\) |
| Answer» E. | |
| 163. |
Inductive reactance is defined as the opposition offered by the __________ of a circuit to the flow of an alternating sinusoidal current. |
| A. | Resistance |
| B. | Inductance |
| C. | Capacitance |
| D. | Voltage |
| Answer» C. Capacitance | |
| 164. |
If the time taken by an alternating quantity to complete one cycle is 2ms, then the frequency of the alternating quantity will be : |
| A. | 5 Hz |
| B. | 500 Hz |
| C. | 50 Hz |
| D. | 5 kHz |
| Answer» C. 50 Hz | |
| 165. |
For an AC circuit, total VA supplied is 3000. If the circuit has a power factor of 0.75 lagging, then the actual power consumed by the circuit is: |
| A. | 2250 W |
| B. | 2000 W |
| C. | 1000 W |
| D. | 4000 W |
| Answer» B. 2000 W | |
| 166. |
A sinusoidal voltage waveform has a frequency of 50 Hz and RMS voltage 30 V. The equation representing the waveform is |
| A. | V = 30 sin 50t |
| B. | V = 60 sin20t |
| C. | V = 42.42 sin314t |
| D. | V = 84.84 sin314t |
| Answer» D. V = 84.84 sin314t | |
| 167. |
Consider an LTI system representing a passive electrical network. If the input is a sinusoidal signal, then the steady-state output of the network is |
| A. | sinusoidal with the same amplitude, frequency, and phase |
| B. | sinusoidal with the same frequency, but possibly different amplitude and phase |
| C. | non-sinusoidal |
| D. | sinusoidal with a different frequency |
| Answer» C. non-sinusoidal | |
| 168. |
A network consisting of a finite number of linear resistor (R), inductor (L), and capacitor(C) elements, connected all in series or all in parallel, is excited with a source of the form\(\mathop \sum \limits_{{\rm{k}} = 1}^3 {{\rm{a}}_{\rm{k}}}\cos \left( {{\rm{k}}{{\rm{\omega }}_0}{\rm{t}}} \right),\) where \(\rm a_k ≠ 0, ω_o ≠ 0\)The source has nonzero impedance. Which one of the following is a possible form of the output measured across a resistor in the network? |
| A. | \({\rm{\;}}\mathop \sum \limits_{{\rm{k}} = 1}^3 {{\rm{b}}_{\rm{k}}}\cos \left( {{\rm{k}}{{\rm{\omega }}_0}{\rm{t}} + {\phi _{\rm{k}}}} \right),{\rm{where\;}}{{\rm{b}}_{\rm{k}}} \ne {{\rm{a}}_{\rm{k}}},\forall {\rm{k}}\) |
| B. | \({\rm{\;}}\mathop \sum \limits_{{\rm{k}} = 1}^4 {{\rm{b}}_{\rm{k}}}\cos \left( {{\rm{k}}{{\rm{\omega }}_0}{\rm{t}} + {\phi _{\rm{k}}}} \right),{\rm{where\;}}{{\rm{b}}_{\rm{k}}} \ne 0,\forall {\rm{k}}\) |
| C. | \(\mathop \sum \limits_{{\rm{k}} = 1}^3 {{\rm{a}}_{\rm{k}}}\cos \left( {{\rm{k}}{{\rm{\omega }}_0}{\rm{t}} + {\phi _{\rm{k}}}} \right)\) |
| D. | \(\mathop \sum \limits_{{\rm{k}} = 1}^3 {{\rm{a}}_{\rm{k}}}\sin \left( {{\rm{k}}{{\rm{\omega }}_0}{\rm{t}} + {\phi _{\rm{k}}}} \right)\) |
| Answer» B. \({\rm{\;}}\mathop \sum \limits_{{\rm{k}} = 1}^4 {{\rm{b}}_{\rm{k}}}\cos \left( {{\rm{k}}{{\rm{\omega }}_0}{\rm{t}} + {\phi _{\rm{k}}}} \right),{\rm{where\;}}{{\rm{b}}_{\rm{k}}} \ne 0,\forall {\rm{k}}\) | |
| 169. |
In a certain single-phase ac circuit the instantaneous voltage is given by v = V sin(ωt + 30°) p.u. And the instantaneous current is given by i = I sin (ωt – 30°) p.u. Hence the per unit value of reactive power is |
| A. | ¼ |
| B. | ½ |
| C. | √3/4 |
| D. | √3/2 |
| Answer» D. √3/2 | |
| 170. |
A circuit consumes average power of 4 kW. If the reactive power associated with the circuit is 3 kVAr lagging, then the power factor of the circuit is: |
| A. | 0.8 lagging |
| B. | 0.75 lagging |
| C. | 0.6 lagging |
| D. | 0.7 lagging |
| Answer» B. 0.75 lagging | |
| 171. |
A series R-L-C circuit is connected to a 25 V source of variable frequency. The circuit current is found to be a maximum of 0.5 A at a frequency of 400 Hz and the voltage across C is 150 V. Assuming ideal components, the values of R and L are respectively |
| A. | 50 Ω and 300 mH |
| B. | 12.5 Ω and 0.119 H |
| C. | 50 Ω and 0.119 H |
| D. | 12.5 Ω and 300 mH |
| Answer» D. 12.5 Ω and 300 mH | |
| 172. |
In the circuit shown, if v(t) = 2 sin(1000 t) volts, R = 1 kΩ and C = 1 μF, then the steady-state current i(t), in milliamperes (mA), is |
| A. | sin(1000 t) + cos(1000 t) |
| B. | 2 sin(1000 t) + 2 cos(1000 t) |
| C. | 3 sin(1000 t) + cos(1000 t) |
| D. | sin(1000 t) + 3 cos(1000 t) |
| Answer» D. sin(1000 t) + 3 cos(1000 t) | |
| 173. |
In a two-element series network, the instantaneous voltages across the elements aresin 314 t and \(3\sqrt 2 \sin \left( {314\;t + 45^\circ } \right)\) The resultant voltage across the combination is expressed as V cos (314t + θ). Then the values of V and θ are |
| A. | 5 and 36.8° |
| B. | 3.5 and 36.8° |
| C. | 5 and -53.2° |
| D. | 3.5 and -53.2° |
| Answer» B. 3.5 and 36.8° | |
| 174. |
In the circuit shown in the figure the equivalent impedance seen across terminals A, B is |
| A. | 16/3) Ω |
| B. | (8/3) Ω |
| C. | (8/3 + 12)Ω |
| D. | None of the above |
| Answer» C. (8/3 + 12)Ω | |
| 175. |
Consider the following values for the circuit shown below:1. \({V_R} = 100\sqrt 2 \;V\)2. I = 2 A3. L = 0.125 HWhich of the above values is correct? |
| A. | 2 and 3 only |
| B. | 1 and 2 only |
| C. | 1 and 3 only |
| D. | 1, 2 and 3 |
| Answer» B. 1 and 2 only | |
| 176. |
A sinusoidal voltage is represented by θ(t) = Vm sin ωt with standard notations. Which one of the following represents the average value of this voltage for half cycle of the wave? |
| A. | \(\frac{2V_m}{\pi}\) |
| B. | \(\frac{V_m}{\pi}\) |
| C. | \(\frac{\pi V_m}{2}\) |
| D. | 0 |
| Answer» C. \(\frac{\pi V_m}{2}\) | |
| 177. |
In an RLC series circuit R = 10 Ω, L = 5 H, C = 5 F. Output voltage is measured across the capacitor. The system is |
| A. | Over damped |
| B. | Under damped |
| C. | Critically damped |
| D. | Oscillatory |
| Answer» B. Under damped | |
| 178. |
An alternating voltage is given by the expression v = 200 sin (314t + a/3) V. The maximum value and frequency of the voltage are respectively __________. |
| A. | 200 V and 25 Hz |
| B. | 200 V and 100 Hz |
| C. | 200 V and 50 Hz |
| D. | 100√2 V and 50 Hz |
| Answer» D. 100√2 V and 50 Hz | |
| 179. |
In a certain series resonant circuit VC = 125 V, VL = 125 V and VR = 40 V. The source voltage is |
| A. | 250 V |
| B. | 125 V |
| C. | 290 V |
| D. | 40 V |
| Answer» E. | |
| 180. |
In a sinusoidal wave, average current is always ________ rms current |
| A. | Equal to |
| B. | Less than |
| C. | Greater than |
| D. | Can’t be determined |
| Answer» C. Greater than | |
| 181. |
An Inductive Reactance function: |
| A. | opposes alternating current |
| B. | opposes direct current |
| C. | allows alternating current |
| D. | allows alternating current and direct current. |
| Answer» B. opposes direct current | |
| 182. |
For an alternating voltage or current, one alternation is equal to: |
| A. | one half cycle |
| B. | two half cycles |
| C. | one quarter cycle |
| D. | three half cycles |
| Answer» B. two half cycles | |
| 183. |
An AC current is given by i = 100 sin 100πt A. It will achieve a value of 50 A at: |
| A. | 1/900 s |
| B. | 1/100 s |
| C. | 1/600 s |
| D. | 1/300 s |
| Answer» D. 1/300 s | |
| 184. |
For the circuit given below, what is the approximate value of the phase angle between the current I and VOUT? |
| A. | 30° |
| B. | 45° |
| C. | 60° |
| D. | 75° |
| Answer» C. 60° | |
| 185. |
Parameters for an RLC circuit are R = 2 Ω, L = 1 H, C = 1 F. If these are connected in series first and then in parallel, the system response for both the circuits will be |
| A. | underdamped, undamped |
| B. | critically damped, overdamped |
| C. | critically damped, underdamped |
| D. | under damped, critically damped |
| Answer» D. under damped, critically damped | |
| 186. |
In a given AC circuit there is a phase difference of π/2 between current and voltage. When the current is at its peak voltage is zero. The circuit is |
| A. | Resistive |
| B. | Inductive |
| C. | Capacitive |
| D. | Can’t say |
| Answer» E. | |
| 187. |
For a pure resistance supplied through a sinusoidal voltage, the phase difference between the voltage and current phasors will be _______. |
| A. | 0° |
| B. | 45° |
| C. | 180° |
| D. | 90° |
| Answer» B. 45° | |
| 188. |
A 10 MVA generator operates at 0.866 pf lag. The reactive power produced is |
| A. | 10 MVAR |
| B. | 8 MVAR |
| C. | 5 MVAR |
| D. | 8.66 MVAR |
| Answer» D. 8.66 MVAR | |
| 189. |
A voltage v(t) = 173 sin (314 t + 10°) is applied to a circuit. It causes a current flow described byi(t) = 14.14 sin (314 t – 20°)The average power delivered is nearly |
| A. | 2500 W |
| B. | 2167 W |
| C. | 1500 W |
| D. | 1060 W |
| Answer» E. | |
| 190. |
A sine wave has a peak value of 12 Volts. Its crest factor is |
| A. | 1.732 |
| B. | 1.11 |
| C. | 1.415 |
| D. | 0.706 |
| Answer» D. 0.706 | |
| 191. |
One sine wave has a positive – going zero crossing at 15° and another sine wave has a positive – going zero crossing at 55°. The angle between the two waveforms is |
| A. | 0° |
| B. | 45° |
| C. | 40° |
| D. | None of the above |
| Answer» D. None of the above | |
| 192. |
Alternating quantities of ______ frequencies can be represented on the same phasor diagram. |
| A. | different |
| B. | negative |
| C. | same |
| D. | multiple |
| Answer» D. multiple | |
| 193. |
If the alternating current equation is i = 64.8 sin 423 t. What will be the average current? |
| A. | 41.21 A |
| B. | 67.45 A |
| C. | 5.99 A |
| D. | 56.78 A |
| Answer» B. 67.45 A | |
| 194. |
A 60% lagging power factor implies that the load is |
| A. | inductive |
| B. | capacitive |
| C. | inductive or capacitive |
| D. | resistive |
| Answer» B. capacitive | |
| 195. |
Determine the total power (in kW) consumed by a 3-phase delta connected system supplied by a line voltage of 230 V, if the phase current is 30 A and the current lags the voltage by 30 degree |
| A. | 14.62 |
| B. | 15.62 |
| C. | 16.62 |
| D. | 17.93 |
| Answer» E. | |
| 196. |
In a series RC circuit, the values of R = 10 Ω and C = 25 nF. A sinusoidal voltage of 50 MHz is applied and the maximum voltage across the capacitance is 2.5 V. The maximum voltage across the series combination will be nearly |
| A. | 172.7 V |
| B. | 184.5 V |
| C. | 196.3 V |
| D. | 208.1 V |
| Answer» D. 208.1 V | |
| 197. |
A sinusoidal wave v = 100 sin (314.15 t). What is its instantaneous value at 0.02 s and 0.005 s? |
| A. | 0; 100 |
| B. | 100; 0 |
| C. | 10; 100 |
| D. | 100; 10 |
| Answer» B. 100; 0 | |
| 198. |
Consider the following equations of two alternating sinusoidal voltages having the same angular frequency ωe1 = 2 sin (ωt)\({e_2} = 6\sqrt 2 \sin \left( {\omega t + \frac{\pi }{4}} \right)\;\)The equation for the resultant voltage is given by: |
| A. | \({e_r} = 8.71\sin \left\{ {\omega t + {{\tan }^{ - 1}}\frac{1}{{3\sqrt 2 }}} \right\}V\) |
| B. | \({e_r} = 10\sin \left\{ {\omega t + {{\tan }^{ - 1}}\frac{3}{4}} \right\}V\) |
| C. | \({e_r} = 8.71\sin \left\{ {\omega t + {{\tan }^{ - 1}}\left( {3\sqrt 2 } \right)} \right\}V\) |
| D. | \({e_r} = 10\sin \left\{ {\omega t + {{\tan }^{ - 1}}\frac{4}{3}} \right\}V\) |
| Answer» C. \({e_r} = 8.71\sin \left\{ {\omega t + {{\tan }^{ - 1}}\left( {3\sqrt 2 } \right)} \right\}V\) | |
| 199. |
Consider the following circuit and determine the power loss in the resistor of branch ‘ab’. (Given: supply voltage = 220 V) |
| A. | 1000 W |
| B. | 2300 W |
| C. | 1040 W |
| D. | 5674 W |
| Answer» D. 5674 W | |
| 200. |
How many degrees of phase represents one full cycle? |
| A. | 360 |
| B. | 180 |
| C. | 270 |
| D. | 90 |
| Answer» B. 180 | |