A magnetic substance has a susceptibility -0.05 at 300 K. The magnetic susceptibility at 600 K is:

-0.05

The correct answer is Option (3) → -0.05

The given susceptibility is -0.05.

The given susceptibility is negative, which shows that the substance is diamagnetic in nature. For diamagnetic substances, magnetic susceptibility does not depend on temperature and remains nearly constant even when the temperature changes.

Therefore, when the temperature increases from 300 K to 600 K, the susceptibility remains unchanged.

Hence, the magnetic susceptibility at 600 K will still be −0.05.