Question

Statement -I: For practical purposes, the earth is used as reference at zero potential in electrical circuits.

Statement -II : The electrical potential of a sphere of radius $R$ with charge $Q$ uniformly distributed on the surface is given by $\frac{Q}{4\pi\epsilon_0 R}$ and for earth, $R$ is very large.

• A. Statement-I is True, Statement-II is True and Statement-II is a correct explanation for Statement-I.
• B. Statement-I is True, Statement-II is True and Statement-II is NOT a correct explanation for Statement-I.
• C. Statement-I is True, Statement-II is False.
• D. Statement-I is False, Statement-II is True.

Answer 1

Answer: (A)

Statement-I is True, Statement-II is True and Statement-II is a correct explanation for Statement-I.

Answer 2

Statement I is true as Earth is conventionally assigned zero potential for practical electrical referencing. Statement II correctly states the potential of a charged sphere ($V = \frac{Q}{4\pi\epsilon_0 R}$) and that Earth's radius is large. This implies that for Earth, the potential is very small for a finite charge, justifying its use as a zero potential reference due to its stability.