Nuclei - Result Question 89

91. The most penetrating radiation of the following is

[1997]

(a) gamma-rays

(b) alpha particles

(c) beta-rays

(d) $X$-rays

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Answer:

Correct Answer: 91. (a)

Solution:

  1. (a) The penetrating power of radiation is directly proportional to the energy of its photon.

Energy of a photon $=\frac{h c}{\lambda} \propto \frac{1}{\lambda}$

$\therefore$ Penetrating power $\propto \frac{1}{\lambda}$

$\lambda$ is minimum for $\gamma$-rays, so penetrating power is maximum of $\gamma$-rays.