A bar magnet is cut into two equal halves along a plane parallel to the magnetic axis. The one parameter which remains unchanged is

intensity of magnetisation

The correct answer is Option (1) → intensity of magnetisation

When a bar magnet is cut along a plane parallel to its magnetic axis:

- Each half becomes a smaller bar magnet.

- Magnetic moment is halved, pole strength is halved, magnetic field lines change.

- Intensity of magnetisation (magnetic moment per unit volume) remains the same.

Final Answer: intensity of magnetisation