MCQs of Alternating Current

Alternating Current MCQs

MCQs of Alternating Current

Showing 151 to 160 out of 168 Questions

151.

A resistor of R = 6 Ω, an inductor of L = 1 H and a capacitor of C = 17.36 μF are connected in series with an A.C. source. The Q-factor is _____

(a)	80
(b)	2.37
(c)	40
(d)	3.72

152.

What should be the value of self inductance of an inductor that should be connected to 220 V, 50 Hz supply, so that a maximum current of 0.9 A flows through it ?

(a)	1.1 H
(b)	2 H
(c)	11 H
(d)	5 H

153.

The peak value of an alternating current is 5 A and its frequency is 60 Hz. The r.m.s. value and time taken to reach the peak value of the current starting from zero are _____ and _____ respectively.

(a)	3.536 A; 4.167 ms
(b)	3.536 A; 15 ms
(c)	6.07 A; 10ms
(d)	2.536 A; 4.167 ms

154.

A circuit is made up of a resistance of 1

Ω

and an inductance of 5.5 mH in series. If an alternating source of 200 V and 50

H_{Z}

is connected with the circuit, then what will be the phase difference between current and voltage in the circuit ?

(a)	$\tan^{- 1} π$
(b)	$\tan^{- 1} (\frac{π}{2})$
(c)	$\tan^{- 1} (\frac{π}{4})$
(d)	$\tan^{- 1} (\frac{π}{3})$

155.

In case of a step-up transformer, transformation ratio is 4:1. If a Laclanche cell having emf 1.5 V is connected across the primary coil, then what is the voltage across the secondary coil ?

(a)	1.5 V
(b)	3 V
(c)	6 V
(d)	zero

156.

A resistor of 30

Ω

inductor of inductive reactance 10

Ω

and capacitor reactance 10

Ω

are connected in series with an A.C. voltage source

V = 300 \sqrt{2} \sin (ω t)

. The current in the circuit will be _____

(a)	10 A
(b)	30 A
(c)	20 A
(d)	100 A

157.

In R-C, A.C. circuit maximum voltage and maximum currents are 100 V and 1.1 A respectively. If X_C = 60 Ω and R= 80 Ω then power consumed in the circuit will be _____

(a)	176.0 W
(b)	44.0 W
(c)	88.0 W
(d)	22.0 W

158.

The output power in step-up transformer used in practice is _____

(a)	greater then the input power
(b)	equal to the input power
(c)	less then the input power
(d)	None of the above

159.

A lamp consumes only 50% maximum power applied in an A.C. circuit. What will be the phase difference between applied voltage and circuit current ?

(a)	$\frac{π}{6} r a d$
(b)	$\frac{π}{4} r a d$
(c)	$\frac{π}{3} r a d$
(d)	$\frac{π}{2} r a d$

160.

An electric current has both D.C. and A.C. components D.C component of 8 A and A.C. component is given as I = 6 sin ωt A. So I_rms value of resultant current is _____

(a)	8.05 A
(b)	11.58 A
(c)	9.05 A
(d)	13.58 A

Showing 151 to 160 out of 168 Questions