Step 1: Use the formula for torque on a magnetic moment.
The torque \( \tau \) on a bar magnet in a magnetic field is given by:
\[
\tau = \vec{M} \times \vec{B}
\]
where \( \vec{M} \) is the magnetic moment and \( \vec{B} \) is the magnetic field induction.
Step 2: Conclusion.
Thus, the torque exerted on the magnet is \( \vec{M} \times \vec{B} \).
Final Answer:
\[
\boxed{\vec{M} \times \vec{B}}
\]