Question 53: Magnetism and Matter

Question

A bar magnet having a magnetic moment of 2.0 $	imes$ 10
5
JT
$-$1
, is placed along the direction of uniform magnetic field of magnitude B 
 = 14 $	imes$ 10
$-$5
T. The work done in rotating the magnet slowly through 60$^\circ$ from the direction of field is :

Accepted Answer

$U =  - \overrightarrow M \,.\,\overrightarrow B $
So ${U_f} - {U_i} =  - MB(1 - \cos 	heta )$
$ =  - 14J$
So $W =  - \Delta U = 14J$

Answer

14 J

Answer

8.4 J

Answer

4 J

Answer

1.4 J

Magnetism and Matter

A bar magnet having a magnetic moment of 2.0 \times 10 5 JT -1 , is placed along the direction of uniform magnetic field of magnitude B = 14 \times 10 -5 T. The work done in rotating the magnet slowly through 60^\circ from the direction of field is :

Choose the correct answer: