Question

Two concentric conducting thin spherical shells A and B having radii r_A and r_B (r_B > r_A) are charged to Q_A and - Q_B (lQ_B| > |Q_A|). The electrical potential along a line, (passing through the centre  is)

Answer 1

Correct option (c)

Explanation:

(lQ_B| > |Q_A|) (given). Inside the shell B, the potential is a constant and negative.

But V_A inside r_A is positive and greater than that of  B because r_A < r_B. Upto r_A, one as hence positive potential. Beyond  r_A , V_A  ∝ (1/r),  this is > V_B, one gets the course ∝  1/r .  At  B, the negative potential is more therefore the potential line is still negative. (c) explains all these factors.