An air cored coil has self inductance of 0.1 H . A soft iron core of relative permeability 1000 is introduced and the number of turns is reduced to ( 1 10 )^ th . The value of self inductance is now

Step-by-step solution

aligned & L = ₀ ~N ^2 ~A l & ~L ^ = ₀ _ r ( ~N ^ )^2 ~A l = ₀ 1000 ( N 10 )^2 ~A l aligned When, _ r =1000 and N = 1 10 , aligned & L ~L ^ = 0.1 ~L ^ = ₀ ~N ^2 ~A l l ₀ 1000 ( N 10 )^2 ~A & 0.1 ~L ^ = 1 10 & ~L ^ =0.1 10=1 H aligned