MCQs of Moving Charges & Magnetism

Moving Charges & Magnetism MCQs

MCQs of Moving Charges & Magnetism

Showing 11 to 20 out of 123 Questions

11.

A charged particle gains energy due to _____ .

(a)	electric field
(b)	magnetic field
(c)	both these fields
(d)	none of these fields.

12.

Equal currents are passing through two very long and straight parallel wires in mutually opposite directions. They will _____ .

(a)	attract each other
(b)	repel each other
(c)	lean towards each other
(d)	neither attract nor repel each other.

13.

A charged particle is moving in a uniform magnetic field. Then _____ .

(a)	its momentum changes but kinetic energy does not change
(b)	its momentum and kinetic energy both change
(c)	neither the momentum nor kinetic energy changes.
(d)	Kinetic energy changes but the momentum does not change.

14.

If the speed of a changed particle moving through a magnetic field is increased, then the radius of curvature of its trajectory will _____ .

(a)	decease
(b)	increase
(c)	not change
(d)	become half

15.

An electron performs circular motion of radius r, perpendicular to a uniform magnetic field B. The kinetic energy gained by this electron in half revolution is _____

(a)	$\frac{1}{2} m v^{2}$
(b)	$\frac{1}{4} m v^{2}$
(c)	zero
(d)	$πrBev$

16.

Two concentric rings are kept in the same plane. Number of turns in both the rings is 20. Their radii are 40 cm and 80 cm and they carry electric currents of 0.4 A and 0.6 A respectively, in mutually opposite directions. The magnitude of the magnetic field produced at their centre is _____ T.

(a)	$4 μ_{0}$
(b)	$2 μ_{0}$
(c)	$\frac{10}{4} μ_{0}$
(d)	$\frac{5}{4} μ_{0}$

17.

A particle of mass m has an electric charge q. This particle is accelerated through a potential difference V and then entered normally in a uniform magnetic field B. It performs a circular motion of radius R. The ratio of its charge to the mass

(\frac{q}{m})

is = _____ [

(\frac{q}{m})

is also called specific charge.]

(a)	$\frac{2 V}{B^{2} R^{2}}$
(b)	$\frac{V}{2 BR}$
(c)	$\frac{VB}{2 R}$
(d)	$\frac{mV}{BR}$

18.

A proton, a deuteron ion and an α-particle of equal kinetic energy perform circular motion normal to a uniform magnetic field B. If the radii of their paths are r_p, r_d and r_α respectively then _____[Here q_d =q_p, m_d = 2m_p]

(a)	r_α= r_p > r_d
(b)	r_α= r_d> r_p
(c)	r_α> r_d> r_p
(d)	r_α= r_d= r_p

19.

Two very long conducting parallel wires are separated by a distance d from each other and equal currents are passed through them in mutually opposite directions. A particle of charge q passes through a point, at a distance

\frac{d}{2}

from both wires, velocity v perpendicular to the plane formed by the wires. The resultant magnetic force acting on this particle is _____ .

(a)	$\frac{μ_{0} Iqv}{2 πd}$
(b)	$\frac{μ_{0} Iqv}{πd}$
(c)	$\frac{2 μ_{0} Iqv}{πd}$
(d)	zero

20.

A charged particle is moving with velocity

\vec{v}

in a uniform magnetic field

\vec{B}

. The magnetic force acting on it will be maximum when _____

(a)	$\vec{v} and \vec{B} are in same direction$
(b)	$\vec{v} and \vec{B} are in opposite direction$
(c)	$\vec{v} and \vec{B} are mutually perpendicular$
(d)	$\vec{v} and \vec{B}$ make an angle of 45° with each other

Showing 11 to 20 out of 123 Questions