Question

24. Four point charges are placed at the four corners of a square in the two ways (i) and (ii) as show
below. Will the (1) electric field (1) Electric potential, at the centre of the square, be the same
different in the two configurations and why?
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Answer 1

Answer:

Electric Potential at centre in both the cases is zero. But Electric field in case (I) is

$4 \sqrt{2} \frac{kq}{l {}^{2} }$

and in case (ii) Electric field will also be zero.

Explanation:

Distance of all corners from centre is same so due to two negative charges Electric Potential at centre is

$- 2 \sqrt{2} \frac{kq}{l }$

and due to two positive charges it is

$2 \sqrt{2} \frac{kq}{l}$

so net Electric Potential will be zero at centre in both the cases. This is zero Electric Potential is Scalar.

Similarly you can calculate Electric field(it is vector)