Which of the following statements about solid conductors in electrostatics is (are) true?
(I) The electric fie)d inside the conductor is always zero
(II) The electric potential inside the conductor is always zero
(III) Any net charge is on the surface

Options

A. I only
B. III only
C. II and III only
D. I and III only

Answer

To determine which statements about solid conductors in electrostatics are true, we will analyze each statement based on the properties of conductors.

### Step-by-Step Solution:

1. **Statement I: The electric field inside the conductor is always zero.**
- In electrostatics, when a conductor is in equilibrium, the free charges within the conductor redistribute themselves in such a way that the electric field inside the conductor becomes zero. This occurs because any electric field would cause the charges to move until they reach a state where there is no net electric field acting on them. Therefore, this statement is **true**.

2. **Statement II: The electric potential inside the conductor is always zero.**
- While the electric field inside the conductor is zero, this does not imply that the electric potential is zero. The electric potential inside the conductor is constant and equal to the potential on the surface of the conductor. The potential can be a non-zero value depending on the charge distribution on the surface. Thus, this statement is **false**.

3. **Statement III: Any net charge is on the surface.**
- In electrostatics, any excess charge placed on a conductor will reside on its surface. This is because the charges repel each other and will move to the outer surface to minimize their potential energy. Therefore, this statement is **true**.

### Conclusion:
- Statement I is true.
- Statement II is false.
- Statement III is true.

The correct options are **I and III**.