Question

The mutual inductance M₁₂ of coil 1 with respect to coil 2 ______.

1. increases when they are brought nearer.
2. depends on the current passing through the coils.
3. increases when one of them is rotated about an axis.
4. is the same as M₂₁ of coil 2 with respect to coil 1.

विकल्प

• a and b

• b and c

• c and d

• a and d

Answer 1

a and d

Explanation:

Mutual Induction: Whenever the current passing through a coil or circuit changes, the magnetic flux linked with a neighbouring coil or circuit will also change. Hence an emf will be induced in the neighbouring coil or circuit. This phenomenon is called ‘mutual induction’.

The mutual inductance M₁₂ of coil 1 w.r.t. coil 2 increases when they are brought nearer and is the same as M₂₁ of coil 2 with respect to coil 1.

M₁₂, i.e., mutual inductance of solenoid S₁ with respect to solenoid S₂ is given by

`M_12 = (mu_0N_1N_2pir_1^2)/l`

Where signs are as usual.

Also, M₂₁, i.e., mutual inductance of solenoid S₂ with respect to solenoid S₁ is given by

`M_21 = (mu_0N_1N_2pir_1^2)/l`

So, we have M₁₂ = M₂₁ = M