somebody help me with these ques please.?

Question

A rectangle has a length of 2d and a height of d. Each of the following three charges is located at a corner of the rectangle: +q1 (upper left corner), +q2 (lower right corner), and -q (lower left corner). The net electric field at the (empty) upper right corner is zero. Find the magnitudes of q1 and q2. Express your answers in terms of q.

Answer 1

Interesting...

Given that Ex at (2d, d)=0

E=F/q=k(Q/R^2)
Ex=E1+E2+E3=
=k(q1/(4d^2) + q2/(5d^2) - q3/d^2))=
Then we have
(k/d^2)(q1/4+q2/5-q3)=0

Or

Q1/4+2q2/5-q3=0 then

q=q3=(4q1+5q2)/20

if q1=q2

then q1=q2=20q/9=2.2q

I hope that helps.

Answer 2

A