Question

Two point charges $ +q $ and $ +4q $ are located at $ x=0 $ and $ x=L $ respectively. The location of a point on the $ x- $ axis at which the net electric field due to these two points charges is zero, is

• A. $ L/3 $
• B. $ 2L $
• C. $ 4L $
• D. $ 8L $

Answer 1

Answer: (A)

The location of a point on the $ x- $ axis, at which the net electric field due to these two point charges is zero, from $ +{{q}_{1}}, $ charge is $ =\frac{L}{1+\sqrt{\frac{{{q}_{2}}}{{{q}_{1}}}}}=\frac{L}{1+\sqrt{\frac{4q}{q}}}=\frac{L}{3} $