Question

(a) Define mutual inductance and write its SI unit. 

(b) A square loop of side á’ carrying a current I₂ is kept at a distance ‘x’ from an infinitely long straight wire carrying a current I₁ as shown in the figure. Obtain the expression for the resultant force acting on the loop.

Answer 1

(a) Co-efficient of mutual induction or mutual inductance of two coils: is equal to the amount of magnetic flux linked with one coil when unit current flows through the neighbouring coil. 

Mathematically, 

ϕ ∝ I

If I = 1, 

ϕ = M × 1

⇒ M = ϕ 

The S.I unit of M is henry (H) 

(b) The force on BC and AD are equal and opposite, 

Therefore, 

The net force on them is zero.