A small coil C with N = 200 turns is mounted on one end of a balance beam and introduced between the poles of an electromagnet as shown in figure. The cross sectional area of coil is A= 1.0 cm2, length of arm OA of the balance beam is \[l=30\,cm.\] When there is no current in the coil the balance is in equilibrium. On passing a current I = 22 mA through the coil the equilibrium is restored by putting the additional counter weight of mass \[\Delta m=60\,mg\] on the balance pan. Find the magnetic induction at the spot where coil is located.

A small coil C with N = 200 turns is mounted on one end of a balance b

1.	A small coil C with N = 200 turns is mounted on one end of a balance beam and introduced between the poles of an electromagnet as shown in figure. The cross sectional area of coil is A= 1.0 cm2, length of arm OA of the balance beam is \[l=30\,cm.\] When there is no current in the coil the balance is in equilibrium. On passing a current I = 22 mA through the coil the equilibrium is restored by putting the additional counter weight of mass \[\Delta m=60\,mg\] on the balance pan. Find the magnetic induction at the spot where coil is located.
A.	0.4 T
B.	0.3 T
C.	0.2 T
D.	0.1 T
Answer» B. 0.3 T