MCQs of Magnetism and Matter

Magnetism and Matter MCQs

MCQs of Magnetism and Matter

Showing 11 to 20 out of 145 Questions

11.

A straight steel wire of length l has magnetic moment m. If the wire is bent in the form of a semicircle, the new value of the magnetic dipole moment is

(a)	m
(b)	$\frac{2 m}{π}$
(c)	$\frac{m}{2}$
(d)	$\frac{m}{π}$

12.

A place, where the vertical component of Earth's magnetic field is zero has the angle of dip equal to

(a)	0^°
(b)	45^°
(c)	60^°
(d)	90^°

13.

At a place on Earth, the horizontal component of Earth's magnetic field is

\sqrt{3}

times its vertical component. The angle of dip at this place is _____ .

(a)	0
(b)	$\frac{π}{2} rad$
(c)	$\frac{π}{3} rad$
(d)	$\frac{π}{6} rad$

14.

A place where the horizontal component of Earth's magnetic field is zero lies at

(a)	geographic equator
(b)	geomagnetic equator
(c)	one of the geographic poles
(d)	one of the geomagnetic poles

15.

When a paramagnetic substance is brought near a north pole or a south pole of a bar magnet, it

(a)	experiences repulsion
(b)	experiences attraction
(c)	does not experience attraction or repulsion
(d)	experiences attraction or repulsion depending upon which pole is brought near to it.

16.

A magnetic needle kept on horizontal surface oscillates in Earth's magnetic field. If the temperature of this needle is raised beyond the Curie temperature of the material of the needle, then _____ .

(a)	the periodic time of oscillation will decrease.
(b)	the periodic time of oscillation will increase.
(c)	the periodic time of oscillation will not change.
(d)	the needle will stop oscillating.

17.

A bar magnet of length l, pole strength 'p' and magnetic moment

' \vec{m}'

is split

\frac{l}{2}

into two equal pieces each of length. The magnetic moment and pole strength of each piece is respectively _____ and _____ .

(a)	$\vec{m}, \frac{p}{2}$
(b)	$\frac{\vec{m}}{2}, p$
(c)	$\frac{\vec{m}}{2}, \frac{p}{2}$
(d)	$\vec{m}, p$

18.

Magnetization for vacuum is _____ .

(a)	negative
(b)	positive
(c)	infinite
(d)	zero

19.

A bar magnet of magnetic moment

\vec{m}

is placed in uniform magnetic field

\vec{B}

such that

\vec{m} ∥ \vec{B}

. In this position, the torque and force acting on it are _____ and _____ respctively.

(a)	0, 0
(b)	$\vec{m} \times \vec{B}, m B$
(c)	$\vec{m} \cdot \vec{B}, m B$
(d)	$\vec{m} \cdot \vec{B}, \vec{m} \times \vec{B}$

20.

Relative permeabilty of a substance is 0.075. Its magnetic susceptibility is

(a)	0.925
(b)	-0.925
(c)	1.075
(d)	-1.075

Showing 11 to 20 out of 145 Questions