NEET Questions Solved


 

The electric potential at the surface of a charged solid sphere of insulator is 20V. The value of electric potential at its centre will be

1.  30V

2.  20V

3.  40V

4.  Zero

(1)

For a solid charged non-conducting sphere, for an inside point at distance r from center

V=kQ2R3(3R2-r2)At center, r=0Vcenter=3kQ2r

At surface r=R, Vs=kQR Vcenter=3Vs2                   =32X20 = 30V

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