Tag: magnetism

Quizzes (14) Questions (113)

Questions Related to magnetism

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

How will you quantize the relative permeability of a paramagnetic substance ?

  1. Much more than one

  2. Slightly more than one

  3. Less than one but greater than zero

  4. Zero
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Paramagnetic substances are those which are attracted slightly in the direction of the magnetic field. As such, the magnetic permeability of these materials is slightly greater than $1$. 
Similarly, diamagnetic materials are those which are repelled slightly away from the direction of magnetic field. These materials have their permeability slightly less than $1$.
And ferromagnetic materials are those which are attracted very strongly and their permeabilities are much higher than $1$.

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

The relative permeability is represented by $\mu _r$ and the susceptibility by $\chi$ for a magnetic substance. Then, for a paramagnetic substance. Then, for a paramagnetic substance 

  1. $\mu _r> 1, \chi >0$
  2. $\mu _r> 1, \chi < 0$
  3. $\mu _r > 1, \chi >0$
  4. $\mu _r < 1, \chi < 0$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Susceptence $(\chi) = \dfrac{B-B _0}{B _0}$


Where $B _0$ is external applied magnetic field and $B$ is magnetic field in presence of paramagnetic substance.
Since dipoles in paramagnetic substance align in direction of applied magnetic filed, therefore $B > B _0$

And $B$ is bit more than $B _0$
$\Rightarrow \chi > 0$

And also $\mu _r = \chi + 1$
$\Rightarrow \mu _r  > 0 + 1$
$ \Rightarrow \mu _r > 1$
Therefore option A is correct.

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

According to  molecular orbital theory, the paramagnetism of $O _{2}$  molecule is due to presence of 

  1. Unpaired electrons in the bonding $\sigma $ molecular orbital
  2. Unpaired electrons in the anti- bonding $\sigma $ molecular orbital
  3. Unpaired electron in the bonding $\pi $ molecular orbital
  4. Unpaired electrons in the anti - bonding $\pi $ molecular obrital
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

According to molecular orbital theory, the electronic configuration of the oxygen molecule places its last two electrons into degenerate anti-bonding pi star molecular orbitals. Because these two electrons remain unpaired, the O2 molecule exhibits paramagnetism.

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

Which of the following is paramagnetic  in nature ? 

  1. $N _{2}$
  2. $C _{2}$
  3. $B _{2}$
  4. $O _{2}^{2+}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Molecular orbital theory shows that B2 has 10 electrons in bonding orbitals and 4 in antibonding, resulting in a bond order of 1 and two unpaired electrons in pi 2p orbitals, making it paramagnetic. O2 2+ has 14 electrons and is diamagnetic, while N2 and C2 are also diamagnetic with all paired electrons.

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

An atom is paramagnetic if it has :

  1. an electric dipole moment

  2. no magnetic moment

  3. a magnetic moment

  4. no electric dipole moment
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Paramagnetism arises from the presence of unpaired electrons in an atom or molecule, which generate a net magnetic moment. When placed in an external magnetic field, these magnetic moments are attracted. Thus, a paramagnetic atom is characterized by having a nonzero magnetic moment.

Multiple choice physics magnetism and matter paramagnetic material classification of magnetic material magnetism

A paramagnetic substance when placed in an externally applied non-uniform magnetic field tends to ___________.

  1. increase the applied field

  2. decrease the applied field

  3. vary the applied field

  4. change the applied field
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Paramagnetic substances are the substances which are feebly attracted by a magnet. When a non-uniform external magnetic field is applied to a paramagnetic substance the magnetic field tries to aligned the magnetic moment in the direction of the field 

Completely alignment is however not possible, on account of thermal vibration. A better allingement can be achieved by increasing the strength of the applied magnetic field.