$α,β$ and $γ$ rays emitted by a radioactive substance are allowed to pass through a region containing a magnetic field at right angles to their path. The energy gained will be

zero for all of them

The correct answer is Option (4) → zero for all of them

In a magnetic field, the force acts perpendicular to the velocity of charged particles. Therefore, no work is done by the magnetic field on the particles.

✅ α and β rays are charged; γ rays are neutral.

Energy gained by all particles in the magnetic field = 0