Current of 2A passing through a coil of 100 turns gives rise to a magnetic flux of `5 xx 10^(-3)` Wb per turn. The magnetic energy associated will coil is ____

Options

A. `5xx10^(-3)` J
B. `0.5xx10^(-3)` J
C. 5 J
D. 0.5 J

Answer

D

Explanation

The total flux associated with coil of N turn and passing current I.
`N phi = LI`
`therefore L=(N phi)/I`…(1)
The energy linked the coil
`U=1/2LI^2`
`therefore U=1/2 xx (Nphi)/I xx I^2` [ `because` from eqn. (1)]
`therefore U=1/2 xx N phiI`
`=1/2xx100xx5xx10^(-3)xx2`
`therefore` U=0.5 J