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The inner and outer radii of a spherica...

The inner and outer radii of a spherical capacitor are `r_1 and r_2` respectively. When the inner surface is earthed . The outer sphere is given a charge +Q , then the charge on the inner surface is

A

A.`(Q(r_1-r_2))/(r_2)`

B

B.`(Q(r_2-r_1))/(r_1)`

C

C.`(Qr_2)/(r_1)`

D

D.`(-Qr_1)/(r_2)`

Text Solution

Verified by Experts

The correct Answer is:
D
`Q.. = Q-Q.`
`= Q-(Q(r_b-r_a))/r_b`
`Q.. = (Qr_a)/r_b`
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