A uniformly charged ring of radius R and total charge q contains a point charge Q at its centre. Consider one semicircular half of the ring. Which statements are correct?
Select all that apply

Question

A uniformly charged ring of radius R and total charge q contains a point charge Q at its centre. Consider one semicircular half of the ring. Which statements are correct?

G1 Physics · Accepted Answer

The central charge produces on the ring a radial force density. For one semicircle, F h a l f F_half F h ​ a l f = ∫ d F p a r a l l e l F_parallel F p ​ a r a l l e l = kQq/(πR²). The increase of ring tension is ΔT = kQq/(2πR²). At the two cut ends, the two tension forces together give 2ΔT = kQq/(πR²), which equals the net force exerted by Q on that semicircular half. Therefore A, B and C are correct.