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Question
Arrange the α, β, and γ radiation in ascending order of their biological damage. Give reason.
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Solution
α < β < γ
- An α-particle rapidly loses its energy as it moves through a medium, and therefore its penetrating power is quite small. It can penetrate only through 3 - 8 cm in air. It can easily be stopped by a thin card sheet or a thick paper.
- The penetrating power of β-particles is greater than that of the α-particles. They can pass through nearly 5 m in air, through thin card sheet, and even through thin aluminum foil, but a 5 mm thick aluminum sheet can stop them.
- Whereas, the penetrating power of γ-rays is high. It is about 104 times that of α-particles and 102 times that of β-particles. They can pass through 500 m in air or through a 30 cm thick sheet of iron. A thick sheet of lead is required to stop them.
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