Case: Read the passage and answer the question.
Conductors contain mobile charge carriers. In metallic conductors, these charge carriers are electrons. In a metal, the outer (valence) electrons part away from their atoms and are free to move. These electrons are free within the metal but not free to leave the metal. The free electrons form a kind of ‘gas’; they collide with each other and with the ions and move randomly in different directions. In an external electric field, they drift against the direction of the field. The positive ions made up of the nuclei and the bound electrons remain held in their fixed positions.
Consider the following statements about a conductor in the static situation:
Statement 1: The electrostatic potential is not constant throughout the volume of the conductor.
Statement 2: \( E=0 \) inside the conductor.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Statement 1 is false, but Statement 2 is true.
Statement 1 The electrostatic potential is not constant throughout the volume of the conductor. — False. In the static situation the field is zero inside the conductor. On the surface, the field has no component along the surface. So no work is done in moving a test charge anywhere within the conductor or on its surface. Hence the potential is the same at every point of the volume and on the surface.
Statement 2 \( E=0 \) inside the conductor. — True. From the passage, the free electrons drift whenever a field acts on them. In the static situation they have spread themselves so that the field is zero everywhere inside.
NCERT (2026-27):
Electrostatics of Conductors – “… Since E = 0 inside the conductor and has no tangential component on the surface, no work is done in moving a small test charge within the conductor and on its surface. That is, there is no potential difference between any two points inside or on the surface of the conductor.”
Electrostatics of Conductors – “… In the static situation, the free charges have so distributed themselves that the electric field is zero everywhere inside. Electrostatic field is zero inside a conductor.”