9
Rationalised 2023-24
Physics
170
 EXAMPLE 6 9
=




21
0
2
0
2
(
)
µ
µ
n Al
B
n
        [from Eq (6 15)]
2
0
21
µB Al
=
(b)
The magnetic energy per unit volume is,
B
B
U
u
=V
            (where V is volume that contains flux)
      
UB
Al
=
      
2
20
B
µ
=
(6