Question

If the current flowing in a coil is reduced to half of its original value, the relation between the new energy (E₂) and the original energy (E₁) stored in the coil will be

(A) E₂ = E₁

(B) E₂ = 2E₁

(C) E₂ = \(1\over2\)E₁

(D) E₂ = \(1\over4 \)E₁

Answer 1

The Correct option is  D)  E₂ = \(1\over4\)E₁  

Explaination  

 Current is become half of the given value. 

\(E={1\over2}Li^2\) 

i.e. 

\({E_2\over E_1}={({i_2\over i_1})^2}=({1\over2})^2\)         __{current halfs i₂=1/2 i_1}

_{\(E_2={1\over4}E_1\)}