TS EAMCET 14-Sep-2020 Shift 1 Solved Paper

Since electric potential is a scalar quantity. So, the potential at the centre is given as
V=K‌

q

R

+K‌

q

R

+....9 times
V=‌

9Kq

R

...(i)
Since, electric field is a vector quantity. So, the electric field cancel each other for the charges of opposite corner of polygon.
Only 10q−(10−1)q=10q−9q=q will contribute the electric field at the centre of polygon. Thus,
E=K‌

q

R2

....(i)
From Eqs. (i) and (ii), we get
∴‌‌‌

V

E

=‌

‌ 9Kq R

Kq R2

=9R