Beta rays

(i) Nature: The direction in which these rays get deflected in an electric and magnetic field indicates that these rays are negatively charged. They carry 1 unit of negative charge and negligible mass as I have told in my very previous article. So the removal of beta particle decreases the increases the atomic number by 1 unit because neutron get transformed into proton for its removal as it is told in previous articles. They are actually fast moving electrons.

(ii) Velocity: The velocity of beta rays are generally greater than those of alpha rays and their velocity also depends upon the nature of source.

(iii) Ionizing Power: Due to their lower momentum (due to the negligible mass of beta rays) they have low ionizing power than alpha rays.

(iv) Penetrating power: Because of their smaller mass and higher speed, beta rays are much more penetrating than alpha particles. For example, beta rays can be stopped only by an aluminum sheet of thickness 10 mm.

(v) Effect on photographic plate and zinc sulphide screen: Like alpha rays, beta rays also effect the photographic plate but the effect in this case is much more. On the other hand beta rays do not have any significant effect on the zinc sulphide screen. This is on account of their lower kinetic energy than that of alpha rays.