<b>Statement:</b> The electrostatic field inside a conductor in equilibrium is always zero.<br><br><b>Reason:</b><br><br><b>1. Free electrons in conductor</b><br>A conductor contains a large number of <b>free electrons</b> that can move easily through the material.<br><br><b>2. Effect of any internal field</b><br>If any electric field existed inside, the free electrons would experience a force F = qE and would start moving.<br><br><b>3. Redistribution of charges</b><br>These moving electrons redistribute themselves on the surface of the conductor in such a way that they create an <b>internal field that exactly cancels</b> the external field.<br><br><b>4. Equilibrium condition</b><br>In electrostatic equilibrium, no net current flows. This is only possible when the net field inside the conductor is <b>zero</b>.<br><br><b>Conclusion:</b> E_inside = 0