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प्रश्न
Arrange the α, β, and γ radiation in ascending order of their biological damage. Give reason.
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उत्तर
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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संबंधित प्रश्न
A radioactive source emits three types of radiations.
Name the radiations which are deflected by the electric field.
The diagram in figure shows a radioactive source S placed in a thick lead walled container. The radiations given out are allowed to pass through a magnetic field. The magnetic field (shown as ×) acts perpendicular to the plane of paper inwards. Arrows shows the paths of the radiation A, B and C.

- Name the radiations labelled A, B and C.
- Explain clearly how you used the diagram to arrive at the answer in part (a).
In following Figure shows a mixed source R of alpha and beta particles in a thick lead walled container. The particles pass through a magnetic field in a direction perpendicular to the plane of paper inwards as shown by ×.
- Show in the diagram how the particles get affected.
- Name the law used in part (a).

[Hint: Alpha particles will deflect to the left while beta particles to the right]
In following Figure shows a radioactive source S in a thick lead walled container having a narrow opening. The radiations pass through an electric field between the plates A and B.

- Complete the diagram to show the paths of α, β and γ radiations.
- Why is the source S kept in a thick lead walled container with a narrow opening?
- Name the radiation which is unaffected by the electrostatic field.
- Which radiation is defleced the most. Given reason.
- Which among the three radiations causes the least biological damage?
Explain why alpha and beta particles are deflected in an electric or a magnetic field, but gamma rays are not deflected in such a field.
Is it possible to deflect γ - radiations in a way similar to α and β -particles, using the electric or magnetic field? Give reasons.
State following four properties each of α, β and γ radiations:
- Nature,
- Charge,
- Mass and
- Effect of electric field.
State the speed of each of α, β and γ radiations.
A radioactive substance emits radiations ______.
Compare the ionising powers of α, β and γ radiations.
