During the radioactive decay of a substance,which of the following is $NOT$ emitted?

Radioactive nuclei that are injected into a patient collect at certain sites within their body,undergoing radioactive decay and emitting electromagnetic radiation. These radiations can then be recorded by a detector. This procedure provides an important diagnostic tool called:

$A$ radioactive nucleus of mass $M$ emits a photon of frequency $v$ and the nucleus recoils. The recoil energy will be

In medicine,to destroy cancer cells . . . . . . rays are used.

The energy spectrum of $\beta$-particles [number $N(E)$ as a function of $\beta$-energy $E$] emitted from a radioactive source is

Which of the following can penetrate through an aluminum sheet of $20 \, cm$ thickness?