Question 29

A spherical capacitor consists of two concentric spherical conductors, held in position by suitable insulating supports (Figure). Show

that the capacitance of a spherical capacitor is given by

where *r*1 and *r*2 are the radii of outer and inner spheres, respectively.

Answer

Radius of the outer shell = *r*1

Radius of the inner shell = *r*2

The inner surface of the outer shell has charge +*Q*.

The outer surface of the inner shell has induced charge - *Q*.

Potential difference between the two shells is given by,

Hence, proved.

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A point charge of 2.0 μC is at the centre of a cubic Gaussian surface 9.0 cm on edge. What is the net electric flux through the surface?

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- NCERT Chapter

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