Question

Radioactive substances emit $\gamma $ -rays which are:
A. +ve charged particle
B. -ve charged particle
C. Massive particle
D. Packet of energy

Answer 1

Hint: To answer this question we have to know about $\gamma $ -rays. $\gamma $ -rays are emitted by the radioactive decay of radioactive nuclei. The radioactive nuclides undergo decay to give alpha, beta, gamma, X-rays. $\gamma $ -rays are actually higher energy radiation.

Complete Step by Step Answer:
$\gamma $ -rays are not material particles. It is a high energetic electromagnetic radiation consisting of a packet of energy. It is emitted due to radioactive decay of radioactive nuclide. $\gamma $ -rays does not have any charge. They do not contain any particle or any charged particle. Actually $\gamma $ -rays are neutral.

Gamma ray is also known as gamma radiation that is a penetrating form of electromagnetic radiation releasing from the radioactive decay of radioactive atomic nuclide. It consists of the shortest wavelength electromagnetic waves which are typically shorter than those of X-rays.

Gamma rays are harmful as they cause external hazards. As the gamma ray is the high energetic radiation so, when it passes through a person it causes damaging of the cells in its path. Radioactive substances emit $\gamma $ -rays which are packets of energy.
Thus the correct option is C.

Note: Gamma rays are used in Mossbauer spectroscopy widely. In Mossbauer spectroscopy the nucleus of the ground state absorbs the gamma ray and goes to an excited state and gives a signal.