Electric Flux & Gauss's Law
A point charge is placed inside a cavity within a solid isolated conducting sphere. Consider points and as shown in the figure, where the magnitudes of the electric fields are , respectively. The points and are at the same distance from the center of the solid sphere. The correct option is:
Show answer and solution
Answer: (c)
- Inside the cavity the charge and the induced charge on the cavity wall give a nonzero field, so .
- The conductor shields the outside from the cavity's details; the outer surface gets charge spread uniformly.
- Outside, the field is that of at the sphere's centre, so equal distances give .
- So the answer is (c) .