Two point charges are fixed on the -axis: a charge of at and a charge of at
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
Two point charges are fixed on the y-axis: a charge of +8.0μC at (0,0.12m) and a charge of −2.0μC at (0,−0.12m). The electric potential is defined to be zero at infinity.
(a) Write an algebraic expression for the electric potential V(y) at an arbitrary point on the y-axis.
(b) Determine all point(s) on the y-axis where the potential equals −2.0×105V. Provide complete algebraic work leading to your answer.
(c) Compute the numerical coordinate(s) of the point(s) obtained in part (b) and state them with appropriate sign and units.
(d) Explain whether any of the point(s) you found correspond to positions of stable equilibrium for a small positive test charge released from rest, and justify your conclusion.