Q. Two parallel infinite line charges with linear charge densities $+\lambda$ C/m and $-\lambda$ C/m are placed at a distance of 2R in free space. What is the electric field mid-way between the two line charges?
A) zero
B) $\frac{2\lambda}{\pi\epsilon_0R}$ N/C
C) $\frac{\lambda}{\pi\epsilon_0R}$ N/C
D) $\frac{\lambda}{2\pi\epsilon_0R}$ N/C
Explanation
[Solution] Each line gives $\frac{\lambda}{2\pi\epsilon_0R}$ in the same direction at the midpoint; total $\frac{\lambda}{\pi\epsilon_0R}$. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.