The essential distinction between `X` - rays and `gamma` - rays is that

Options

A. `gamma`-rays have smaller wavelength than X-rays
B. `gamma`-rays emanate from nucleus while X-rays emanate from outer part of the atom
C. `gamma`-rays greater ionising power than X-rays
D. `gamma`-rays are more penetrating than `X`-rays

Answer

B

Explanation

The wavelength of the `gamma`-rays is shorter. However, the main distinguishing feature is the nature of emission.