Question

Which type of radiation is most penetrating?

Answer 1

Electromagnetic radiation contains a wide range of wavelength and frequency which includes radio waves, microwaves, $X -$ rays, gamma rays. This entire range is known as the electromagnetic spectrum. This electromagnetic radiation is produced when an atomic particle is accelerated with the application of an electric field. Visible radiation also forms a very small proportion of electromagnetic radiation.

Complete answer:
The power of any radiation to cross across any matter is defined in terms of the penetrating power of the radiation. Different radiations have different penetrating power.
Penetrating power of the radiation depends upon the various factors like energy level of the radiation, total mass of the particle of radiation, and on the nature of the matter through which radiation needs to cross.
Gamma rays or gamma radiation has penetrating power which is generated from the radioactive decay of nuclei of atoms.
When gamma rays are allowed to fall over the matter it has a tendency to cross the matter up to a larger extent than other radiations. After collision with matter, gamma radiation loses its energy as well its speed and finally stops.
Gamma particles show more penetrating power than $\alpha$ particles as well as $\beta$ particles.

$\therefore$ Gamma radiation shows the most penetrating power.

Note:
Gamma rays are highly harmful to humans because of their ability to cross the matter. Gamma rays easily cross the biological cells and damage them. Gamma rays are a potent hazard for bone marrow as well as other internal organs.