Select the incorrect statement.

Options

A. In electrostatics, electric field intensity close to the surface of a metal is always along the normal
B. Net electric field intensity inside a conductor is always zero
C. Electric field lines do not pass through the conductor in an electrostatic condition
D. Net charge of an isolated system remains conserved

Answer

To solve the question, we need to evaluate each of the four statements given and identify which one is incorrect.

### Step-by-Step Solution:

1. **Evaluate the First Statement:**
- The statement claims that in electrostatics, the electric field intensity close to the surface of a metal is all along the normal (perpendicular) to the surface.
- This is true because the surface of a conductor in electrostatic equilibrium is an equipotential surface. The electric field lines are always perpendicular to equipotential surfaces.

2. **Evaluate the Second Statement:**
- The statement claims that the electric field intensity inside a conductor is always zero.
- This statement is misleading. While it is true that the electric field inside the conducting material of a conductor is zero, it does not mean that the electric field is zero inside the entire conductor if there are charges present. For example, if there is a cavity within the conductor and a charge is placed inside that cavity, the electric field will not be zero inside that cavity. Therefore, this statement is incorrect.

3. **Evaluate the Third Statement:**
- The statement claims that electric field lines do not pass through the conductor in an electrostatic condition.
- This is correct. In electrostatic equilibrium, the electric field inside a conductor is zero, meaning that electric field lines cannot pass through the conductor.

4. **Evaluate the Fourth Statement:**
- The statement claims that the net charge of an isolated system remains conserved.
- This is true and is a fundamental principle of charge conservation. In an isolated system, the total charge remains constant over time.

### Conclusion:
Based on the evaluations:
- The first statement is correct.
- The second statement is incorrect.
- The third statement is correct.
- The fourth statement is correct.

Thus, the answer to the question is that the **second statement** is the incorrect one.