Which type of particles are not deflected by a magnetic field?

Gamma rays are a form of electromagnetic radiation and are not charged particles, which is why they are not deflected by a magnetic field. In a magnetic field, charged particles are influenced by the Lorentz force, which acts on them due to their charge and velocity. Since gamma rays have no charge and behave like light waves, they pass through magnetic fields unaffected.

In contrast, alpha particles and beta particles are charged. Alpha particles consist of two protons and two neutrons, while beta particles are electrons (or positrons) that carry a negative (or positive) charge. Both types of particles experience a force when they move through a magnetic field, leading to their deflection.

Neutrons, though they are neutral and therefore share some characteristics with gamma rays, behave differently. Neutrons experience faint magnetic interactions when in close proximity to magnetic fields due to their magnetic moment, but they are primarily affected by nuclear forces at the atomic level and are not deflected in the way charged particles are.

Thus, the correct answer identifies gamma rays as the type of particles that do not experience deflection in a magnetic field due to their lack of charge.