Electrons revolving around the nucleus do not fall into the nucleus because of centrifugal force.
Revolving electrons are planetary electrons.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false
D. If assertion is false but reason is true.

Answer

B

Explanation

(b) We know that electrons are revolving around the nucleus ar high speed in circular paths. The centrifugal force (which arises due to rotation of electrons) acting outwards, balances the electrostatic force of attraction (which arises due to attaction between electrons and nucleus) . The prevent the electron from falling into the nucleus. We also know that Rutherford's model of atom is comparable to the "solar system". The nucleus represents the sun whereas revolving electrons represent the planets revolving around the sun. Thusm revolving electrons are also called planetary electrons. Therefore both assertion and reason are true but reason is not a correct explanation of assertion.