Question

Two point charges q₁ = +1μC and q₂ = +4 μc are placed 2 m apart in air. At what distance from q₁ along the line joining the two charges, will the net electric field is zero?

Answer 1

According to question we solve , 

4kq/x² = kq/(1-x)²

{x/(1-x)}² = 4 

x/(1-x) = 2 

x = 2 – 2x 

3x = 2 

x = 2/3