Chapter 16, Problem 4RQ

To determine

The type of ray that has the greatest penetrating power.

Answer to Problem 4RQ

The gamma-ray has the greatest penetrating power.

Explanation of Solution

The alpha particle emitted by an unstable atom has a massive size compared to the other radiation rays. Due to the large size, they cannot penetrate such lightweight materials like paper and clothes.

In the case of beta particles, the size is less as compared to alpha particles. It contains a negative charge on it and travels faster than alpha particles. When a neutron emits a beta particle, then it becomes a proton. The beta particle has more energy than alpha and can penetrate paper and clothes also. But it cannot penetrate a very thin layer of aluminum sheet.

The gamma rays of radioactive atoms are the electromagnetic waves that travel with light speed and it particle behaves like photon (the energy packet of light). The energy of the gamma rays is much larger as compared to visible light and other electromagnetic waves. So it can penetrate through most of the material.

Conclusion:

Therefore, the gamma-ray has the greatest penetrating power.