Question:easy
Which of the following is the most ionizing radiation?
Which of the following is the most ionizing radiation?
Show Hint
High charge plus large mass equals dense ionization over a very short range.
Updated On: Jun 24, 2026
- Alpha
- Beta
- X rays
- Gamma
Show Solution
The Correct Option is A
Solution and Explanation
The key is to separate two opposite ideas that students often mix up: ionizing power versus penetrating power. This question asks for ionizing power, that is, how heavily a radiation deposits charge along its track.
Heavy, highly charged, slow particles dump their energy in a short distance and ionize intensely. The alpha particle fits perfectly: it carries a +2 charge and the mass of a helium nucleus, so it strips electrons aggressively and has a very high linear energy transfer.
Now weigh the alternatives. Beta is just a fast electron with a single negative charge and tiny mass, so its ionization density is much lower. X-rays and gamma are chargeless photons; they cause ionization only second-hand by ejecting electrons, and their ionizing density is the weakest.
The order of ionizing strength runs alpha first, then beta, then the photons. Penetration runs in the reverse order, which is why alpha is blocked by a sheet of paper while gamma needs lead.
\[\boxed{\text{Alpha}}\]
Heavy, highly charged, slow particles dump their energy in a short distance and ionize intensely. The alpha particle fits perfectly: it carries a +2 charge and the mass of a helium nucleus, so it strips electrons aggressively and has a very high linear energy transfer.
Now weigh the alternatives. Beta is just a fast electron with a single negative charge and tiny mass, so its ionization density is much lower. X-rays and gamma are chargeless photons; they cause ionization only second-hand by ejecting electrons, and their ionizing density is the weakest.
The order of ionizing strength runs alpha first, then beta, then the photons. Penetration runs in the reverse order, which is why alpha is blocked by a sheet of paper while gamma needs lead.
\[\boxed{\text{Alpha}}\]
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