MCQs of Moving Charges & Magnetism

Moving Charges & Magnetism MCQs

MCQs of Moving Charges & Magnetism

Showing 51 to 60 out of 123 Questions

51.

Current of 10 A and 2 A are passed through two wires A and B respectively in opposite direction. If the wire A is infinity long and length of the wire B is 2 m, the force action on the conductor B which is situated at 10 cm distance from A will be _____.

(a)	8π×10^-7N
(b)	8×10^-5N
(c)	4π×10^-7N
(d)	5×10^-5N

52.

Electron is rotating in a circular orbit with radius 5.2 x 10^-11 m and with linear speed 2 x 10⁶ ms^-1 in an hydrogen atom around the proton. Find the magnetic field produced at the centre of the orbit.

(a)	12.8 T
(b)	1.18 T
(c)	11.8 T
(d)	zero

53.

A charge Q is uniformly spread over a disc of radius R made from non-conducting material. This disc is rotated about its geometrical axis with frequency f. Find the magnetic field produced at the centre of the disc.

(a)	$\frac{μ_{0} Q f}{R}$
(b)	zero
(c)	$\frac{μ_{0} QR}{f}$
(d)	$\frac{μ_{0} Q f}{2 R}$

54.

An election having 182 eV kinetic energy is moving on a circular path in a magnetic field of 10^-4 T. The speed of the electron is _____.

(a)	4×10^-7ms^-1
(b)	32×10¹⁴ms^-1
(c)	8×10⁶ms^-1
(d)	16×10⁷ms^-1

55.

A circular loop is prepared from a wire of uniform cross section. A battery is connected between any two points on its circumference. The magnetic induction at the centre of the loop is _____ .

(a)	$\frac{μ_{0} I_{1} I_{2}}{4 πR}$
(b)	$\frac{μ_{0} I_{1}}{2 π r}$
(c)	zero
(d)	$\frac{μ_{0} I_{1} I_{2}}{4 π r^{2}}$

56.

if electron velocity is

(2 \hat{i} + 3 \hat{j})

unit and it is subjected to magnetic of

4 \hat{k}

unit , then its _____.

(a)	path will change
(b)	speed will change
(c)	Both (A) and (B ) will change
(d)	None of the above

57.

A particle having 2 C charge passes through magnetic field of 4

\hat{k}

T and some uniform electric field with velocity 25

\hat{j}

. If the Lorentz force acting on it is 400

\hat{i}

N, find the electric field in this region.

(a)	200 $\hat{i}$
(b)	200 $\hat{k}$
(c)	100 $\hat{i}$
(d)	10 $\hat{j}$

58.

To convert galvanometer into an ammeter _____. Is to be connected.

(a)	a small resistance in series with it
(b)	a large resistance in series with it
(c)	a small resistance in parallel with it
(d)	a large resistance in parallel with it

59.

In copper there are 8 x 10²⁸ free (conducting) electrons per cubic meter. A current copper wire having length 1 m and cross-sectional area 8 x 10^-6 m² is placed perpendicularly in the magnetic field of 4 x 10^-3 T. The force acting on this wire is 8.0 x 10^-2 N. Find the drift velocity of the free electron.

(a)	3 x 10⁴ ms^-1
(b)	2 x 10⁴ ms^-1
(c)	2 x 10^-4 ms^-1
(d)	4 x 10^-4 ms^-1

60.

A current flows in conducting wire of length L. if we bend it in a circular form, its magnetic dipole moment would be _____.

(a)	$\frac{I^{2} L}{4 π}$
(b)	$\frac{I^{2} L^{2}}{4 π}$
(c)	$\frac{I L^{2}}{4 π}$
(d)	$\frac{I L}{4 π}$

Showing 51 to 60 out of 123 Questions