Grounded Sphere and Point Charge
A point charge with charge is placed at a distance of from the center of a grounded conducting sphere of radius .
Find the magnitude of force experienced by in newtons.
Details and Assumptions
The answer is 20.
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1 solution
Well using image theory and experience we know that the sphere will induce charge on its surface in such A fashion that the potential on its surface is 0 , (because its grounded)
Now let us imagine that this charge distributon is equivalent to a fictious charge kept somewhere inside the sphere on the line joining the centre and the real charge,
It can be easily checked that a charge of 50 micro coulomb at a distance of (1/2) m to the right( readers right) satisfies this condition .
or a fictous charge of 50 mC placed 3/2 metre away from the charge has an equipotential surface (also 0 potential) which overlaps with the grounded sphere
now the force of interaction can readily be found to be 20N