Question

Compass needle of magnetic moment m placed in a uniform magnetic field, experiences a torque equal to ______.

Options

• `vectau = vec"m" xx vec"B"`

• `vectau = vec"m"*vec"B"`

• `vectau = mu_0(vec"m" xx vec"B")`

• `vectau = 2pi(vec"m" xx vec"B")`

Answer 1

Compass needle of magnetic moment m placed in a uniform magnetic field, experiences a torque equal to `underline(vectau = vec"m" xx vec"B"`).

Explanation:

Torque is vector quantity and is given be cross product of `vec"m" xx vec"B"`. Its magnitude is  m B sin θ.