Step 1: Understanding the setup.
When a metallic stick is rotated in a magnetic field, the emf induced between the ends of the stick is due to the motion of the conductive material in the magnetic field.
The induced emf is given by:
\[
\mathcal{E} = B \omega L^2
\]
where:
- \( B \) is the magnetic field strength,
- \( \omega \) is the angular velocity,
- \( L \) is the length of the stick.
Step 2: Conclusion.
The induced emf between the ends of the stick is:
\[
\mathcal{E} = B \omega L^2
\]