Question

A magnet will cause the greatest deflection of:
A. $\alpha $ -rays
B. $\beta $ -rays
C. $\gamma $ -rays
D. Neutrons

Answer 1

Hint: The radiation or ray which is neutral or uncharged has the highest high penetrating power and is not affected by an electrical and magnetic field. This is because the uncharged rays are not affected by the charge of the nucleus of an atom.

Complete Step by Step Solution:
$\alpha $ -rays consist of $\alpha $ particles. The alpha particles are actually helium atoms. Helium atoms have a mass number of $4$ and atomic number of $2$ . Thus an alpha particle is a positively charged particle and bends its path on penetration in presence of magnetic field.

 $\beta $ -rays consist of beta particles. The beta particles are actually high energetic electrons. Beta particles have lower size and higher negative charge than alpha particles. So beta particles bend more than alpha particles in a given magnetic field.

$\gamma $ -rays are not material particles. It is a high energetic electromagnetic radiation consisting of a packet of energy. $\gamma $ -rays does not have any charge. They do not contain any particle or any charged particle. Actually $\gamma $ -rays are neutral. So they are not affected by magnetic fields.
Neutron is a subatomic particle of an atom. It has no charge and it is not affected by magnetic fields.
Thus the correct option is B.

Note: The particle or ray which is highly charged and has low mass is highly deflected by a magnet or under magnetic field. Among alpha, beta and gamma particles beta particles have low mass and high negative charge so they are highly deflected by magnetic fields.