Question

What is the source of centripetal force, when an electron revolves around the nucleus?

Answer 1

Hint: As a first step, one could define what centripetal force and which motion results in this force. You could also think of the factors affecting this force. Then, you could consider the particular example that is given in the question. Then think of the possible source for centripetal force there.

Complete step-by-step solution:
In the question, we are asked to find the source of centripetal force for an electron that is revolving around the nucleus. Before going to answering the question, let us recall what a centripetal force actually is. It is the force experienced by any object that is undergoing circular motion. For an object undergoing curvilinear motion, the centripetal force is that component of force that is directed towards the centre of curvature or may be the rotational axis. The SI unit of centripetal force is the same as any other force, that is, Newton.
For the example given in the question, that is the electron revolving around the nucleus, there exists an electrostatic force of attraction between the positive nucleus and negative electron. This is the force that provides the centripetal force that is required by the electron in order to continue its motion in its respective orbit.
Hence, we found that the electrostatic force of attraction between electron and nucleus is the source of centripetal force in the given example.

Note: Now, let us list down some other examples for objects that experience centripetal force. They are:
(1) The planets of our solar system that are revolving around the sun.
(2) The car being turned around a corner.
(3) A ball being spun on a string or may be a lasso being twirled.