Properties of в Ray
- • The direction of deflection of p rays in the electric and magnetic fields shows that they carry negative charge. The charge and mass of the particles present in these rays have been determined, and it is found that these particles possess the same charge and mass as that of the electrons. Thus, р-particles are nothing but electrons.
- • As in case of a rays, the velocity of the p rays depends upon the nature of the source. However, being much lighter than the a-particles, р-particles travel at a higher speed than the a-particles. The speed of the р-particles varies from 3% to 99% of that of light, that is in some cases it approaches the velocity of light.
- • In spite of a higher speed than a-particles, р-particles have less momentum or kinetic energy than the a-particles because of their smaller mass. Hence, p-particles have lower ionizing power than a-particles. The ionizing power of р-particles is about 1/100th of that of a-particles.
- • Because of their smaller mass and higher speed, р-particles are much more penetrating than the a-particles. They can penetrate through an aluminium foil several mm in thickness or through a lead sheet about 3 mm in thickness. Their penetrating power is about 100 times greater than that of a rays.
- • Like a rays, p rays affect a photographic plate and the effect is much higher. However, there is no significant effect on a zinc sulphide screen because of their lower kinetic energy.