Q: A magnet of magnetic moment \$20\ CGS\$ units is freely suspended in a uniform magnetic field of intensity \$0.3\ CGS\$ units. The moment of work done in deflecting it by an angle of \$30^{\circ}\$ in \$CGS\$ units is

Work done, \$W = MB (1 - \cos \theta)\$\$= 20\times 0.3(1 - \cos 30^{\circ})\$\$= 6\times \left (1 - \dfrac { {\sqrt{3}}}{2}\right ) = 3(2 - \sqrt {3})\$.

Q: Magnetic moment of bar magnet is \$M\$. The work done in turning the magnet by \$90^o\$ in direction of magnetic field \$B\$ will be

Potential energy of a magnetic moment at an angle \$\theta\$ with the magnetic field = \$-MB\cos\theta\$Thus work done in rotating from angle \$\theta_1\$ to \$\theta_2=MB(cos\theta_1-cos\theta_2)\$\$=MB(cos0^{\circ}-cos90^{\circ})\$\$=MB(1-0)\$\$=MB\$

Question 1

A paramagnetic material is kept in a magnetic field. The field is increased till the magnetization becomes constant. If the temperature is now decreased, the magnetization :

Accepted Answer

As it's clearly visible from the graph that for a paramagnetic material magnetization increases with decrease in temperature.

Question 2

A magnet of magnetic moment $20\ CGS$ units is freely suspended in a uniform magnetic field of intensity $0.3\ CGS$ units. The moment of work done in deflecting it by an angle of $30^{\circ}$ in $CGS$ units is

Accepted Answer

Work done, $W = MB (1 - \cos \theta)$$= 20\times 0.3(1 - \cos 30^{\circ})$$= 6\times \left (1 - \dfrac { {\sqrt{3}}}{2}\right ) = 3(2 - \sqrt {3})$.

Question 3

The permanent magnetic moment of the atoms of a material is not zero. The material  :

Accepted Answer

Unlike paramagnetic materials, the atomic moments in ferromagnetic materials exhibit very strong interactions. These interactions are produced by electronic exchange forces and result in a parallel or antiparallel alignment of atomic moments.This results in permanent non-zero magnetic moment of atoms in these materials.

Question 4

Magnetic moment of bar magnet is $M$. The work done in turning the magnet by $90^o$ in direction of magnetic field $B$ will be

Accepted Answer

Potential energy of a magnetic moment at an angle $\theta$ with the magnetic field = $-MB\cos\theta$Thus work done in rotating from angle $\theta_1$ to $\theta_2=MB(cos\theta_1-cos\theta_2)$$=MB(cos0^{\circ}-cos90^{\circ})$$=MB(1-0)$$=MB$

Magnetism And Matter

Physics
1526 Views

A paramagnetic material is kept in a magnetic field. The field is increased till the magnetization becomes constant. If the temperature is now decreased, the magnetization :

A magnet of magnetic moment $20 C G S$ units is freely suspended in a uniform magnetic field of intensity $0.3 C G S$ units. The moment of work done in deflecting it by an angle of $3 0^{\circ}$ in $C G S$ units is

The permanent magnetic moment of the atoms of a material is not zero. The material :

Magnetic moment of bar magnet is $M$ . The work done in turning the magnet by $9 0^{o}$ in direction of magnetic field $B$ will be

Magnetism And Matter

Physics 1526 Views

A paramagnetic material is kept in a magnetic field. The field is increased till the magnetization becomes constant. If the temperature is now decreased, the magnetization :

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

The permanent magnetic moment of the atoms of a material is not zero. The material :

Magnetic moment of bar magnet is M. The work done in turning the magnet by 90o in direction of magnetic field B will be

Physics
1526 Views

A magnet of magnetic moment $20 C G S$ units is freely suspended in a uniform magnetic field of intensity $0.3 C G S$ units. The moment of work done in deflecting it by an angle of $3 0^{\circ}$ in $C G S$ units is

Magnetic moment of bar magnet is $M$ . The work done in turning the magnet by $9 0^{o}$ in direction of magnetic field $B$ will be