Question

Which force is weakest of all fundamental forces?
(A) Gravitational force
(B) Electromagnetic force
(C) Weak nuclear force
(D) Strong nuclear force

Answer 1

Hint:The nuclear force is of many types. The strong nuclear force is the kind of the attraction between the neutrons and the protons and this helps them to keep the nucleus. The weak nuclear force is not strong and stable and thus it undergoes radioactive decay.

Useful formula:
$F = \dfrac{{GMm}}{{{r^2}}}$

Where $F$ is the force of attraction, $G$ is the gravitational constant, $M$ is the mass of the earth, $m$ is the mass of the body and $r$ is the distance between the objects on the earth.

Complete step by step solution:
The weak nuclear force is the weak force to hold up the nucleus. It is present in the radioactive isotopes like radium, indium etc. They undergo complete nuclear fission or the decay to become stable. The strong nuclear force is formed by the proton and the neutron in the nucleus. Hence they all bind together, and hence the atoms of the strong nuclear force have very small nuclei and their density will be higher. The gravitational force of attraction takes place between the two masses on the earth which is separated by the small distance. This force is the very weakest force. This can be explained by the formula
$F = \dfrac{{GMm}}{{{r^2}}}$
Where the gravitational constant value is $6.674 \times {10^{ - 11}}\,{m^3}K{g^{ - 1}}{s^{ - 2}}$ . This is a very small value. The electromagnetic force causes the interaction between the charged particles. This results in bonding and forming stable compounds.
Hence the option (A) is correct.

Note:The weakest gravitational force that is offered by the earth is mainly from the molten iron and the nickel present in the inner core of the earth. This force is very weak and it is uniform at any surface of the earth. Since it is very weak, it is limited to some distance in the atmosphere. This helps in holding all the organisms, things, air, water etc. on it for survival.