Two point charges are fixed in place in otherwise empty space: charge A has a value…
PHYSICS · Multi-part · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance
Problem
Two point charges are fixed in place in otherwise empty space: charge A has a value of +2.0μC and charge B has a value of +5.0μC. At the instant shown the separation between the centers of the two charges is 0.15m. The reference point of zero electric potential energy is taken to be infinite separation.
Answer the following qualitatively, using clear verbal reasoning that explicitly refers to physical principles.
(a) Predict whether the electric potential energy of the two–charge system at the given separation is positive, negative, or zero, and justify your prediction without performing a numerical calculation.
(b) The separation between the charges is slowly increased to 0.30m. Describe how the magnitude of the system’s electric potential energy changes, and explain the physical reason for that change.
(c) A student claims that no external work is required to increase the separation of the two charges because there is no immediate contact force between them. Clearly explain whether this claim is correct or incorrect, citing relevant physical concepts.