A small conducting sphere of radius initially carries a net charge of
PHYSICS · Multi-part · CBSE · Physics · Current Electricity · Current Electricity
Problem
A small conducting sphere of radius 2.0cm initially carries a net charge of +6.4μC. It is connected to Earth by a straight copper wire for 0.50s. A current sensor placed in series with the wire records a steady current of 25mA during the entire interval. The wire is then disconnected from the sphere.
Assume the sphere remains isolated from other charges during the procedure.
(a) Calculate the total charge that passes through the wire in the 0.50s interval.
(b) Based on your result from part (a), determine whether the sphere is completely neutralized when the wire is removed. Justify your answer without referring to any external data.
(c) Compute the total number of electrons that move between the sphere and Earth during the grounding, and indicate their direction of motion.
(d) If the experiment were repeated with the sphere carrying −6.4μC instead, predict the sign of the measured current. Explain your reasoning in terms of charge carriers.