Question 11 Mark
Peak value of applied alternating voltage in a LR cir- cuit is 5 V. If magnitude of maximum voltage across the ends of resistor is 3 V. then maximum value of voltage across the inductor is
Answer
View full question & answer→(b)4 V
Questions
M.C.Q (1 Marks)
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29 questions · self-marked practice — reveal the answer and mark yourself.
Question 21 Mark
Alternating current cannot be measured by de ammeter because:
Answer
View full question & answer→(b)Average value of current for a complete cycle is zero.
Question 31 Mark
Frequency and potential difference of AC sent to homes in India is:
Answer
View full question & answer→(a)50 Hz, 220 V
Question 41 Mark
Frequency of electric current in alternating current I $=200 \sin \left(60 \pi t+\frac{\pi}{6}\right)$ is :
Answer
View full question & answer→(d)30 Hz
Question 51 Mark
The number of turns in primary and secondary coils of a transformer are 100 and 300 respectively. If in- put power is 60 W, then output power will be:
Answer
View full question & answer→(a)60 W
Question 61 Mark
A transformer increases ac voltage supply from 220 V to 2200 V. If there are 2000 turns in the second- ary coil, then number of turns in the primary coil is:
Answer
View full question & answer→(c)200
Question 71 Mark
Which of the following substance is most suitable to make core of transformer?
Answer
View full question & answer→(a)Soft iron
Question 81 Mark
Potential difference in ac circuit is $V =20 \sin \omega t$ and current flowing is $I =5 \cos \omega t$, then power dissipated in watts is :
Answer
View full question & answer→(a)0
Question 91 Mark
A lamp whose resistance is $280 \Omega$ is joined with an ac source of 200 V . The peak value of current flowing in the lamp is :
Answer
View full question & answer→(a)1.0 A
Question 101 Mark
In an ac circuit, phase of current lags the phase of voltage by an angle of $\frac{\pi}{3}$. The component in the circuit is :
Answer
View full question & answer→(b)R and I
Question 111 Mark
Magnitude of current at half power point in a circuit is:
Answer
View full question & answer→(b)$\frac{I_{\max }}{\sqrt{2}}$
Question 121 Mark
Power factor of LCR circuit in resonance is:
Answer
View full question & answer→(c)1
Question 131 Mark
Resistance of a circuit is $12 \Omega$ and impedance is $15 \Omega$. The power factor of the circuit is :
Answer
View full question & answer→(b)0.8
Question 141 Mark
Phase difference between voltage across the ends of an inductor coil and capacitor in radians is:
Answer
View full question & answer→(a)$\pi$
Question 151 Mark
Phase difference between ac current and emf is $\frac{\pi}{2}$.Which of the following cannot be a component of the circuit?
Answer
View full question & answer→(d)R, L
Question 161 Mark
An electric heater is heated by de and ac respec- tively. The potential difference applied across the ends of heater for both ac and de is same. Heat gener- ated per second will be more:
Answer
View full question & answer→(c)Same in both
Question 171 Mark
Impedance of a circuit of inductance L and resis- tance R is denoted by:
Answer
View full question & answer→(c)$\sqrt{L^2 \omega^2+R^2}$
Question 181 Mark
Magnitude of potential difference across L. C and R in a series LCR circuit is 100 V. If resistor is re- moved, then magnitude of current in the circuit is:
Answer
View full question & answer→(b)Infinite
Question 191 Mark
A pure resistor is joined with a capacitor. The magni- tude of tangent of their phase difference in the cir- cuit is:
Answer
View full question & answer→(c)$1 / C \omega/R$
Question 201 Mark
Resistance of capacitor for high frequency is:
Answer
View full question & answer→(b)Low
Question 211 Mark
The point representing reso- nant condition in the figure given is:
Answer
View full question & answer→(a)A
Question 221 Mark
In an ac circuit, potential differenc is $V =10 \cos \omega t$ and current flowing through is $I =2 \sin \omega t$ then magnitude of power dissipated is :
Answer
View full question & answer→(a)Zero
Question 231 Mark
A direct current of 4 A is flowing through any circuit. Root mean square value of the current is:
Answer
View full question & answer→(a)4 A
Question 241 Mark
An electric bulb is made to work at 12 V dc. When this bulb is joined with an ac source, it gives normal brightness. Peak voltage of ac source is:
Answer
View full question & answer→(b)17 V
Question 251 Mark
Root mean square value of ac voltage $V=$ $200 \sin \left(100 \pi t+\frac{\pi}{2}\right)$ is :
Answer
View full question & answer→(a)$100 \sqrt{2} V$
Question 261 Mark
Alternating current is produced in:
Answer
View full question & answer→(c)Dynamo
Question 271 Mark
L, C and R represent physical quantities-inductance, capacitance and resistance respectively. The one which has same dimensions as time is:
Answer
View full question & answer→(c)$\frac{ L }{ R }$
Question 281 Mark
Maximum value of voltage in an ac circuit is 282 V. The effective magnitude of voltage is:
Answer
View full question & answer→(a)200 V
Question 291 Mark
In an ac circuit, current $I=5 \sin \left(100 t-\frac{\pi}{2}\right)$ ampere and altemating potential difference is $V =200$ sin ( 100 t ). The power dissipated in the circuit is :
Answer
View full question & answer→(b)Zero W