Question

Ionization power and penetration range of radioactive radiation increases in the order

• A. $\lambda, \beta, \alpha \, \, and \, \lambda, \beta, \alpha$ respectively
• B. $\lambda, \beta, \alpha \, \, and \, \alpha, \beta, \lambda$ respectively
• C. $\alpha, \beta, \lambda \, \, and \, \alpha, \beta, \lambda$ respectively
• D. $\alpha, \beta, \lambda \, \, and \, \lambda, \beta, \alpha$ respectively

Answer 1

The Correct Option is B

Because of large mass and large velocity, $\alpha$-particles have large ionising power. Each $\alpha$-particle produces thousands of ions before being absorbed. The $\beta$-particles ionise the gas through which they pass, but their ionising power is only $\frac{1}{100}$ th that of $\alpha$-particles. $\gamma$-rays have got small ionising power.
Because of large mass, the penetrating power of $\alpha$-particles is very small, it being $1 / 100$ times that to $\beta$-rays and $1 / 10000$ times that of $\gamma$-rays. $\alpha$-particles can be easily stopped by an Aluminium sheet, only $0.02$ mm thick. $\beta$-particles have very small mass, so their penetrating power is large. $\gamma$-rays have very large penetrating power.