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A Dhingra
#4
Feb6-13, 07:34 AM
P: 196
Energy due to a charge is infinite?

Work is W=∫F.dx .
So in it if i apply the limits some distance r to ∞, i would get,
W = ∫(kQq/x2) dx = -kQq/x, x from r to ∞,
= -kqQ(1/∞-1/r) = -kQq/r..
this is definitely not ∞.

But I was thinking that the test charge is moving continuously (with non uniform, decreasing acceleration) almost for infinite time. In that case the sum of all the small patches under the curve should have given infinite energy(I was considering kinetic energy, on v-t graph)....but that doesn't seem to be happening...