The couple acting on a magnet of length 10cm and pole strength 15A-m, kept in a field of `B=2xx10^(-5)`, at an anlge of `30^(@)` is

Options

A. `1.5xx 10^(-5)`N-m
B. `1.5 xx 10^(-3)`N-m
C. `1.5 xx 10^(-2) N-m`
D. `1.5 xx 10^(-6)N-m`

Answer

A

Explanation

As ,` tau=MB sin theta =(mxx 2l) xx 2 xx 10^(-5) sin 30^@`
`= 15 xx 10 xx 10^(-2) xx 2 xx 10^(-5) xx (1)/(2)`
`= 1.5 xx 10^(-5)`N-m