Question

Two long cylindrical wires of radius 'a' have linear charge densities $+\lambda$ and $-\lambda$ respectively. The distance between them is na (n > 1). Find the capacitance per unit length of the system.

• A. $\pi {ϵ}_0$
  
• B. $\frac{\pi {ϵ}_0}{n}$
• C. $\frac{\pi {ϵ}_0}{ln\left(n\right)}$
• D. $\frac{2\pi {ϵ}_0}{ln\left(n\right)}$

Answer 1

The correct option is C $\frac{\pi {ϵ}_0}{ln\left(n\right)}$