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Q.
The penetrating powers of $\alpha, \beta$ and $\gamma$ radiations, in decreasing order are
Nuclei
Solution:
The penetrating power of alpha rays, beta rays, and gamma rays varies greatly. Alpha particles can be blocked by a few pieces of paper. Beta particles pass through a paper but are stopped by aluminum foil. Gamma rays are most difficult to stop and require concrete, lead or other heavy shielding to block them.