A metal ring of radius `r =0.5m` with its plane normal a unifrom magnetic field `B` of induction `0.2T` carries a current `I=100A` The tension in newtons developed in the ring is

Options

A. 100
B. 50
C. 25
D. 10

Answer

D

Explanation

Considering dl segment of ring.
`implies2 T sin ((d theta)/2)=idlBimpliesT((d theta)/2)=idlB`
`impliesT d theta =iRd theta B` {R is radius} `rarr T=iRB`
`(100)(0.5)(0.2)=10N`