Write a short note on alpha and beta particles

Rutherford studied the behavior of alpha-particles. Some important characteristics of alpha-particles are; Alpha particles when placed in an electrical field get deflected towards negative plate. This shows that α-particles are positively charged.

alpha (α-) particles

Rutherford studied the behavior of alpha-particles. Some important characteristics of alpha-particles are;

(i) Alpha particles when placed in an electrical field get deflected towards negative plate. This shows that α-particles are positively charged.

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(ii) Alpha particles carry two units of positive charge, and four units of mass. Thus alpha particles (α-particles) are doubly charged helium ion, He²⁺.

(iii) The α-particles travel at a speed of about 2× 10⁷ m s^-1. This speed is about one –fifteenth that of light.

(iv) The α-particles have very small penetrating power. Alpha particles can be stopped by thin(less than 0.1 mm) sheets of metals or mica.

(v) The α-particles ionize the gas through which they pass.

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(vi) The α-particles affect the photographic plate.

beta (β-) particles

Beta particles were found to have properties similar to those of cathode rays. Some important characteristics of beta (β-) particles are;

(i) The β- particles get deflected towards positive plate in an electrical field. Thus, β- particles are negatively charged particles. β- Particles have mass equal to that of an electron. Thus, β- particles are electrons.

(ii) β- Particles travel at a speed of up to 90% of the speed of the light.

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(iii) β- Particles cause ionization of the gas through which they pass. The ionizing power of β- particles is much less than that of α- particles.

(iv) β- Particles are more penetrating. These can however, be stopped by about 1 cm thick aluminum sheet.