Question

Penetration power of proton is:
(A) More than electron
(B) Less than electron
(C) More than neutron
(D) None of these

Answer 1

The penetration power of any species or substance is defined as its ability to penetrate or pass through a material. We can relate mass of a species to its penetrating power as inversely proportional to each other. Therefore, to know about the penetration power of a proton, we will first compare the masses and sizes of proton, electron and neutron.

Complete answer:
We know that the penetration power of any species (electron, proton and neutron) is defined as its ability to penetrate or pass through a material. This is a property of waves. Any matter or substance has dual nature which means it shows some properties of particles and some properties of waves.
The penetration power of any particle is inversely proportional to its mass, charge and directly proportional to its energy.
Now, the masses of electron, proton and neutron are in the order:
$electron < neutron \approx proton$
We can see that among the above given particles, the electron has the highest penetrating power.
Therefore, the penetration power of protons is less than that of an electron.

Hence, the correct option is (B) Less than electrons.

Note:
We should also note that the penetration power of a particle depends upon its ionization energy. It is inversely proportional to the ionizing energy. This means that a particle with high ionizing energy has low penetration power and a particle with low ionizing energy has high penetration power.