Question

 A non conducting spherical shell of diameter 10 cm has a charge of 1.6 × 10 -4 C. A charge of 20 C is placed at a distance of 10 cm from its centre, then force between them will be

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Answer 1

A non conducting spherical shell of diameter 10 cm has a charge of 1.6 × 10 -4 C.

radius of non conducting spherical shell, r = 5cm = 0.05m

A charge of 20C is placed at a distance 10cm or 0.1m from its centre.

first of all, we have to find electric field due to spherical shell at d = 10cm from its centre.

here, you can see observation point is outside the sphere. so, electric field due to spherical shell at that point will be E = kq/d² , where q = 1.6 × 10^-4 C

so, E = 9 × 10^9 × 1.6 × 10^-4/(0.1)² N/C

= 14.4 × 10^5/0.01 N/C

= 1.44 × 10^8 N/C

now force between spherical shell and charge , F = QE

= 20C × 1.44 × 10^8 N/C

= 28.8 × 10^8 N

= 2.88 × 10^9 N