In the situation shown in the figure a particle having charge q is executing simple harmonic motion of amplitude A and time period T in front of a CONDUCTING EARTHED SPHERE of radius R. The reading of the voltmeter when the charge particle is at its mean position(at a distance r from the sphere's centre) is? The attempt at a solution I'm confused about the way to approach the problem. There could be so many ways in which the sphere could get a different potential, (like due to the electric field of the charge q, due to changing magnetic field because of the oscillating charge) that I am unable to get a pinpoint solution. Do help me with this one. Look at the attached diagram for clear details.