MCQs of AC Circuits (Basic Electrical Engineering - 3110005)

Basic Electrical Engineering (3110005) MCQs

MCQs of AC Circuits

Showing 81 to 90 out of 117 Questions

81.

“The direction of an induced e.m.f. is always such that it tends to set up a current opposing the motion or the change of flux responsible for inducing that e.m.f.”, this is the statement for?

(a)	Fleming’s left hand rule
(b)	Fleming’s right hand rule
(c)	Faraday’s law
(d)	Lenz’s law

82.

Which, among the following, is the formula for induced emf?

(a)	e=dϕ /dt
(b)	e=dt/dϕ
(c)	e=t*ϕ
(d)	e=t²ϕ

83.

Which of the following expressions is correct with respect to relative permeability?

(a)	B = µ_rµ₀/H
(b)	B = µ_rµ₀H
(c)	B = µ_r/µ₀H
(d)	B = µ_rµ₀/H²

84.

A sine wave has a afrequency of 50 Hz, Its angular frequency is _____________________ radian/second.

(a)	100 $π$
(b)	50 $π$
(c)	25 $π$
(d)	5 $π$

85.

The period of a wave is

(a)	the same as frequency
(b)	time required to complete one cycle
(c)	expressed in amperes
(d)	none of the above

86.

The period of a sine wave is 0.02 seconds, its frequency is

(a)	20 Hz
(b)	30 Hz
(c)	40 Hz
(d)	50 Hz

87.

A heater is rated as 230 V, 10 kW, A.C. The value 230 V referes to

(a)	average voltage
(b)	r.m.s. voltage
(c)	peak voltage
(d)	none of the above

88.

If two sinusoids of the same frequency but of different amplitudes and phase angles are subtracted the resultant is

(a)	a sinusoid of same frequency
(b)	a sinusoid of half the original frequency
(c)	a sinusoid of double the frequency
(d)	not a sinusoid

89.

The peak value of a sine wave is 200 V. Its average value is

(a)	127.4 V
(b)	141.4 V
(c)	282.8 V
(d)	200 V

90.

If two sine waves of same frequency have a phase difference of pi radina, then

(a)	both will reach their minimum values at same instant
(b)	both will reach their maximum values at same instant
(c)	when one wave reaches its maximum value, the other will reach its minimum value
(d)	none of the above

Showing 81 to 90 out of 117 Questions