Tag: classification of magnetic material

Questions Related to classification of magnetic material

Out of given paramagnetic substance (Calcium, Chromium, Oxygen and Tungsten) which substance has maximum susceptibility?

  1. Calcium

  2. Chromium

  3. Oxygen

  4. Tungsten


Correct Option: B
Explanation:

Susceptibility at the standard temperature, $T=300K$

Calcium $\rightarrow 1.9\times 10^{-5}$ 
Chromium $\rightarrow 2.7\times 10^{-4}$
 Oxygen $\rightarrow 2.1\times 10^{-6}$
Tungsten $\rightarrow 6.8\times 10^{-5}$
Chromium have maximum susceptibility.
The correct option is B.

A paramagnetic liquid is taken in a U-tube and arranged so that one of its limbs is kept between pole pieces of the magnet. The liquid level in the limb is

  1. goes down

  2. rises up

  3. remains same

  4. first goes down and then rise


Correct Option: B
Explanation:

When a paramagnetic liquid is taken in U-tube and one arm is placed between the poles of strong magnet, the liquid is feebly attracted by the magnet. Therefore, the level of the solution in the arm rises.

The magnetic susceptibility of a paramagnetic material at $-73^0$ is $0.0075$, its value at $-173^0$C will be

  1. $0.0045$

  2. $0.0030$

  3. $0.015$

  4. $0.0075$


Correct Option: C
Explanation:
Given,
$X=0.0075 \,\,at\,\,\, T=-73^{\circ}$
Curie's law, $X=\cfrac{C}{T}$
$X _{1} \propto \cfrac{1}{T _{1}}$
$\therefore \cfrac{X _{1}}{X _{2}}=\cfrac{T _{2}}{T _{1}}$
$X _{2}=X _{1}\times \cfrac{T _{1}}{T _{2}}=0.0075\times \cfrac{273-73}{2.73-173}=0.015$

Assertion : Paramagnetic substances get weakly attracted to a magnet.
Reason : They have tendency to move from a region of strong magnetic field to weak magnetic field

  1. If both assertion and reason are true and reason is the correct explanation of assertion.

  2. If both assertion and reason are true and reason is not the correct explanation of assertion.

  3. If assertion is true but reason is false.

  4. If both assertion and reason are false


Correct Option: C
Explanation:

Paramagnetic substances have tendency to move from a region of weak magnetic field to strong magnetic field i.e., they get weakly attracted to a magnet.

Consider the following statements I and II.
(I) Paramagnetism is explained by domain theory 
(II) Susceptibility of a diamagnetic substance is independent of temperature.
Identify the correct choice from the following. 

  1. Both I and II are correct

  2. Both I and II are incorrect

  3. I is correct and II is incorrect.

  4. I is incorrect and II is correct


Correct Option: D

Assertion(A) : Earth's magnetic field inside a closed iron box is less as compared to the outside.
Reason(R) : The magnetic permeability of iron is low.

  1. Both A, R are true and R is the correct explanation of A

  2. Both A, R are true and R is not correct explanation of A

  3. A is true R is false

  4. A is false R is true


Correct Option: C

The meniscus of a liquid contained in one of the limbs of a narrow U-tube is held electromagnet with the meniscus in line with the field. The liquid is seen to rise. This indicates that the liquid is

  1. anti-ferromagnetic

  2. paramagnetic

  3. diamagnetic

  4. non-magnetic


Correct Option: B
Explanation:

Paramagnetic liquid tends to flow from region of weaker magnetic fields to stronger magnetic fields..

Metals getting magnetised by orientation of atomic magnetic moments in external magnetic field are called

  1. diamagnetics

  2. paramagnetics

  3. ferromagnetics

  4. antimagnetics


Correct Option: B
Explanation:

In paramagnetic metals, magnetism is acquired by orientation of atomic magnetic  dipoles.

The purpose of soft iron cylinder between the pole pieces of the horse-shoe magnet in a moving coil galvanometer is 

  1. to increase the magnetic induction in the polar

    gap

  2. to evenly distribute the magnetic lines of force

  3. to provide a radial magnetic field

  4. to reduce the magnetic flux leakage in the polar

    gap


Correct Option: A
Explanation:

Soft iron cylinder is placed between the pole pieces of the horse-shoe magnet in a moving coil galvanometer to increase the magnetic induction in the polar gap. Soft iron is paramagnetic which increases magnetic induction when placed in field because atoms in soft iron align in such manner that it increases field.

A bar magnet has been cut equally lengthwise and widthwise to give four equal pieces. The pole strength of each piece as compared to the pole strength of original bar magnet is :

  1. Same

  2. $\displaystyle \frac{1}{8}$

  3. $\displaystyle \frac{1}{4}$

  4. $\displaystyle \frac{1}{2}$


Correct Option: D