MCQs of Electromagnetic Induction

Electromagnetic Induction MCQs

MCQs of Electromagnetic Induction

Showing 21 to 30 out of 113 Questions

21.

The distance between two extreme points of two wings of an aeroplane is 50 m. It is flying at a speed of 360 kmh^-1 in horizontal direction. If the vertical component of the Earth's magnetic field at that place is 2 × 10^-4 Wbm^-2 , the induced emf between these two end points is _____ V.

(a)	0.1
(b)	1.0
(c)	0.2
(d)	0.01

22.

A wheel with 10 metallic spokes each 0.5 m long rotated with a speed of 120 rev/min in a plane normal to the horizontal component of the Earth's magnetic field B_h at a place. If B_h = 0.4 G at the place, what is the induced emf between the axle and the rim of the wheel ? (1 G = 10^-4 T)

(a)	0 V
(b)	0.628 mV
(c)	0.628 μ V
(d)	62.8 μ V

23.

A short-circuited coil is placed in a time-varying magnetic field. Electrical power is dissipated in the form of joule heat due to the current induced in the coil. If the number of turns were to be quadrupled and the wire radius halved, the electrical power dissipated would be _____.

(a)	halved
(b)	the same
(c)	doubled
(d)	quadrupled

24.

The self-inductance of two solenoids A and B having equal length are same. If the number of turns in two solenoids A and B are 100 and 200 respectively, the ratio of the radii of their cross-section will be _____.

(a)	2 : 1
(b)	1 : 2
(c)	1 : 4
(d)	4 : 1

25.

Faraday's law is the consequence of the law of conservation of _____.

(a)	charge
(b)	energy
(c)	magnetic field
(d)	Both (B) and (C)

26.

A magnetic field changes from zero to 2 × 10^-2 T, while acting at a right angle to a coil of area 100 cm² with 50 turns. Time taken to induce an emf of 0.1 V in the coil is _____.

(a)	0.01 s
(b)	0.1 s
(c)	0.5 s
(d)	1 s

27.

A 1.2 m wide railway track is parallel to the magnetic axis. The vertical component of the Earth's magnetic field is 0.5 Gauss. When a train runs on the rails at a speed of 60 km/hr, then the induced potential difference between the ends of its axle will be _____.

(a)	10^-4 V
(b)	2 × 10^-4 V
(c)	10^-3 V
(d)	zero

28.

When

α

is the angle between plane of the coil and magnetic field

\underset{B}{\to}

, flux with the coil is given by

ϕ

= _____

(a)	AB
(b)	$\|\underset{A}{\to} \times \underset{B}{\to}\|$
(c)	$A B \cos α$
(d)	$\underset{A}{\to} \times \underset{B}{\to}$

29.

Nma^-1 is the unit of _____

(a)	magnetic induction (B)
(b)	magnetic flux (Φ)
(c)	self-inductance (L)
(d)	flux density (B)

30.

The length of spoke of a wheel is 0.5 m. The wheel is rotated perpendicular to the magnetic field of 5 × 10^-4 T. The potential difference between the rim of the wheel and its centre is 3.14 mV. Then what will be frequency of the wheel ?

(a)	8 Hz
(b)	12Hz
(c)	16 Hz
(d)	20 Hz

Showing 21 to 30 out of 113 Questions