Question

Consider $\alpha -$particles, $\beta -$particles & $\gamma -$ rays, each having an energy of $0.5MeV$. Increasing order of penetrating of the radiations are:

• A. $\alpha <\beta <\gamma$
• B. $\alpha <\gamma <\beta$
• C. $\beta <\gamma <\alpha$
• D. $\gamma <\beta <\alpha$

Answer 1

Answer: (A)

$\alpha <\beta <\gamma$

$\alpha$ -particles are essentially helium ions, and these are Massive and are Poorly penetrating.

$\beta$ -radiation are fast-moving electrons, and these are slightly more penetrating with respect to $\alpha$-particles

$\gamma$ -radiation are faster moving particles, on the photonic scale. And these have the most penetrating power. They require lead shielding of several mm for safe containment.

Hence answer is Option A