A neutral solid conducting cube rests on an insulated stand in air
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A neutral solid conducting cube rests on an insulated stand in air. At the center of a small spherical cavity located entirely inside the cube (and not touching the outer surfaces) a point charge of +5μC is fixed in place.
Address the following aspects of the resulting electrostatic situation.
(1) Describe qualitatively how excess charge distributes itself (i) on the interior surface of the cavity and (ii) on the exterior surface of the cube.
(2) State the net amount of charge that appears on the cavity surface and justify your answer.
(3) State the net amount of charge that appears on the exterior surface of the cube and justify your answer.
(4) Explain whether an electric field exists just outside any point on the exterior surface of the cube.
(5) A −2nC test charge is released from rest at a point 5cm outside the center of one face of the cube. Describe the initial direction of the net electrostatic force on the test charge and provide reasoning based on your answers above.