Question

Two coils of self-inductance `L_(1)` and `L_(2)` are placed closed to each other so that total flux in one coil is completely linked with other. If `M` is mutual inductance between them, then
A. ` 0.8 ` J
B. ` 8 ` J
C. `16 ` J
D. ` 4 ` J

Answer 1

Correct Answer - B
Stored energy ` U = ( 1 )/( 2 ) Li ^ 2 = ( 1 )/( 2 ) L ( ( E)/( R)) ^ 2 `
Here, `E = 10 V, L = 4 H and R = 5 Omega `
` therefore U = ( 1 )/(2 ) xx 4 xx (( 10)/ ( 5 ))^ 2 J = 8 J `