Question

m along
23. 'n' charges Q, 4Q, 9Q, 16Q ..... are placed at distances of 1, 2, 3 ..... metre from a
point 'O' on the same straight line. The electric intensity at 'O' iS
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Answer 1

SOLUTION :-

Since all charges have same sign and lie on a same straight line, so for calculating electric field intensity we can add them directly i.e,

$E = \frac{KQ}{ {1}^{2} } + \frac{k4Q}{ {2}^{2} } + \frac{k9Q}{ {3}^{2} } ............$

E = KQ + KQ + KQ + ................

E = nKQ ( since , there are " n " charges )

$E = \frac{nQ}{4\pi \ ε0}$