A point charge q is placed inside the cavity of a metallic shell. Whi…

The correct answer is Option (3) → the diagram in Option (3)

In electrostatics the field is zero inside the metal of the shell, and at every conductor surface the field lines are normal to the surface. The charge q induces an equal and opposite charge on the inner surface, so its lines end there. An equal charge q appears on the outer surface, and new lines start from it.

Option (1) — Incorrect. From the figure, the lines run straight through the shell. No line can pass through the metal, where the field is zero.

Option (2) — Incorrect. From the figure, the lines stop at the shell, but they are straight lines from an off-centre charge. So they meet the inner surface and leave the outer surface at a slant. Field lines must meet a conductor surface at right angles.

Option (3) — Correct. From the figure, the lines from q bend to meet the inner surface at right angles. No line exists inside the metal, and outside, new lines leave the outer surface normally.

Option (4) — Incorrect. From the figure, the curved lines cross the shell, so they pass through the metal, where the field must be zero.

NCERT (2026-27):
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.”

Electrostatics of Conductors – “… Thus electrostatic field at the surface of a charged conductor must be normal to the surface at every point.”