Electrostatics Question 783
Question: Three charges -q, +q and +q are situated in X-Y plane at points (0, -a), (0, 0) and (0, a) respectively. The potential at a point distant r (r>a) in a direction making an angle $ \theta $ from Y-axis will be
Options:
A) $ \frac{Kq}{r}( 1-\frac{2a\cos \theta }{r} ) $
B) $ \frac{2kq\cos \theta }{r^{2}} $
C) $ \frac{Kq}{r} $
D) $ \frac{Kq}{r}( 1+\frac{2a\cos \theta }{r} ) $
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Answer:
Correct Answer: D
Solution:
[d] $ V=\frac{Kq.2a\cos \theta }{r^{2}}+\frac{Kq}{r}=\frac{Kq}{r}[ \frac{2a\cos \theta }{r}+1 ] $