Question

$\alpha $-particles can be detected by using
(A) Thin aluminium sheet
(B) Barium sulphate
(C) Zinc sulphide screen
(D) Gold foil

Answer 1

Hint: The composite alpha particle ($\alpha $) is made up of two protons and two neutrons that are firmly bonded together. They are released from the nucleus of some radionuclides during an alpha-decay process, a kind of radioactive decay. An alpha particle is a helium nucleus without electrons ($H{{e}^{2+}}$). It is a positively charged particle. The alpha particles are emitted when a radioactive element undergoes alpha decay.

Complete Step by Step Answer:
All the $\alpha $,$\beta $ and $\gamma $ radiations can be detected with the help of a zinc sulphide ($ZnS$ ) screen. The maximum glow of the ZnS screen is produced by $\alpha $rays. When an $\alpha $-particle strikes the zinc sulphide screen, a flash of light is produced. This leaves a mark and forms a pattern, which is used for the study of $\alpha $-particles.
Correct Option: (C) Zinc sulphide screen.

Additional Information: The alpha rays have low penetration power. It cannot even penetrate a sheet of paper or the outer layer of human skin. Thus, it poses no danger to the human body. The alpha particles are heavy particles and thus move very slowly as compared to the speed of light.

Note: Alpha radiation is easily stopped by a zinc sulphide screen and consists of helium nuclei. A thin aluminium plate can stop beta radiation, which is made up of electrons or positrons, but gamma radiation needs to be shielded by a thick material, such as lead or concrete. Gamma particles are neutral particles.