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Question
Consider the situation in the figure. The work done in taking a point charge from P to Ais WA, from P to B is WB and from P to C is WC.
Options
WA < WB < WC
WA > WB > WC
WA = WB = WC
None of these
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Solution
WA = WB = WC
Points A, B and C lie at the same distance from the charge q, i.e. they are lying on an equipotential surface. So, work done in moving a charge from A to B (WAB) or B toC (WBC) is zero.
Hence, work done in bringing a charge from P to A = WA,
from P to B, WB = WA+WAB = WA
and from P to C, WC = WA + WAB + WBC = WA
Hence, WA = WB = WC
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