Magnetism and Magnetic Materials Test

Question 1
1 / -0

A magnet of magnetic moment M and length 2l is bent at its mid-point such that the angle of bending is 60^o. Now, the magnetic moment is

A
M

B
2M

C
M/2

D
M/√2

Question 2
1 / -0

A magnetic needle is kept in a non-uniform magnetic field. It experiences

A
a torque but no force

B
a force but no torque

C
a force as well as a torque

D
neither a force nor a torque

Question 3
1 / -0

The effective length of a magnet is 31.4 cm and its pole strength is 0.5 A-m. What will be the magnetic moment if it is bent in the form of a semicircle?

A
0.1 A-m²

B
0.01 A-m²

C
0.2 A-m²

D
1.2 A-m²

Question 4
1 / -0

The following question has four choices out of which only one is correct.

A short bar magnet, placed with its axis at 30^owith an external magnetic field of 0.16 T, experiences a torque of magnitude 0.032 J. The magnetic moment of the bar magnet ( in Am²) is

A
4

B
0.2

C
0.5

D
0.5

Question 5
1 / -0

The magnetism of a magnet is due to which of the following?

A
Earth

B
Cosmic rays

C
Spin motion of electrons

D
Pressure of a big magnet inside the Earth

Question 6
1 / -0

For the statements of Assertion and Reason, mark the correct answer.

(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true, but reason is not the correct explanation of assertion.
(c) If assertion is true, but reason is false.
(d) If both assertion and reason are false.

Assertion: A disc-shaped magnet levitates above a superconducting material that has been cooled by liquid nitrogen.
Reason: Superconductors repel a magnet.

A
(a)

B
(b)

C
(c)

D
(d)

Question 7
1 / -0

The following question has four choices out of which only one is correct.

The length of a magnet is larger than its width and height. The time period of its oscillation in a vibration magnetometer is 2 s. The magnet is cut along its length into three equal parts and all the three parts are then placed on each other with their like poles together. The time period of this combination will be

A
2 s

B
2/3 s

C
2√3 s

D
2 /√3 s

Question 8
1 / -0

Materials suitable for making electromagnets should have

A
high retentivity and high coercivity

B
low retentivity and low coercivity

C
high retentivity and low coercivity

D
low retentivity and high coercivity

Question 9
1 / -0

Which of the following is the strongest diamagnetic substance?

A
Aluminium

B
Platinum

C
Bismuth

D
Steel

Question 10
1 / -0

A magnet of magnetic moment 20 CGS units is freely suspended in a uniform magnetic field of intensity 0.3 CGS units. The amount of work done in deflecting it by an angle of 30^o (in CGS units) is

A
6

B
3√3

C
3 (2 – √3)

D
3

Question 11
1 / -0

Which of the following has the highest magnetic permeability?

A
Paramagnetic substance

B
Diamagnetic substance

C
Ferromagnetic substance

D
Vacuum

Question 12
1 / -0

Magnetic susceptibility of a diamagnetic substance

A
decreases with increase in temperature

B
is not affected by temperature

C
increases with increase in temperature

D
first increases and then decreases with increase in temperature

Question 13
1 / -0

At a point on the axial line of a bar magnet of dipole moment M, the magnetic potential is V. What is the magnetic potential due to a bar magnet of dipole moment M/4 at the same point?

A
4 V

B
2 V

C
V/2

D
V/4

Submit Test

Magnetism and M...

Question 1

M

2M

M/2

M/√2

Question 2

a torque but no force

a force but no torque

a force as well as a torque

neither a force nor a torque

Question 3

0.1 A-m2

0.01 A-m2

0.2 A-m2

1.2 A-m2

Question 4

4

0.2

0.5

0.5

Question 5

Earth

Cosmic rays

Spin motion of electrons

Pressure of a big magnet inside the Earth

Question 6

(a)

(b)

(c)

(d)

Question 7

2 s

2/3 s

2√3 s

2 /√3 s

Question 8

high retentivity and high coercivity

low retentivity and low coercivity

high retentivity and low coercivity

low retentivity and high coercivity

Question 9

Aluminium

Platinum

Bismuth

Steel

Question 10

6

3√3

3 (2 – √3)

3

Question 11

Paramagnetic substance

Diamagnetic substance

Ferromagnetic substance

Vacuum

Question 12

decreases with increase in temperature

is not affected by temperature

increases with increase in temperature

first increases and then decreases with increase in temperature

Question 13

4 V

2 V

V/2

V/4

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Question Analysis

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0.1 A-m²

0.01 A-m²

0.2 A-m²

1.2 A-m²