Question

please explanation required​

Answer 1

Answer:- if charge were kept at all corners resultant electric field would have been zero so, removel of one charge would result in the same electric field as due to one charge alone.

so, E = K Q/R^2

I HOPE IT WILL BE HELPFUL FOR YOU!!!

Answer 2

just add one positive and one negative charge at the empty spot

So net charge still remains zero at that place

now due to the positive charge at that place the net field at centre will be zero thus we can remove all the positive charges now.

but still a negative charge is remaining and field due to this negative charge is the resultant field given by KQ/r²