A closely wound solenoid of `2000` turns and area of cross-section `1.5 xx 10^(-4) m^(2)` carries a current of `2.0 A`. It is suspended through its centre and perpendicular to its length, allowing it to turn in a horizontal plane in a uniform magnetic field `5 xx 10^(-2)` tesla making an angle of `30^(@)` with the axis of the solenoid. The torque on the solenoid with the

Options

A. `3 xx 10^(-3)` NM
B. `1.5 xx 10^(-5)` Nm
C. `1.5 xx 10^(-2)` Nm
D. `3 xx 10^(-2)` Nm

Answer

C

Explanation

`tau = MB sin theta = N I A B sin 30^(@)`
`= 2000 xx 1.5 xx 10^(-4) xx 2 xx 5 xx 10^(-2) xx (1)/(2)`
`= 1.5 xx 10^(-2) Nm`