Question
Physics Question on Electric Field
Two point charges +8q and −2q are placed as shown in the figure. The point where the electric field is zero is
A
x=l
B
x=2l
C
x=3l
D
x=4l
Answer
x=2l
Explanation
Solution
Let at a point P at a distance d from −2q charge at which the electric field is zero. ∴E1=E2 4πε01(l+d)28q=4πε01d22q 4d2=(l+d)2 2d=l+d d=l Hence, at x=2l, the electric field is zero due to given charge configuration.