Question

Two infinitely long wires carry linear charge densities $+ \lambda$ and $- \lambda$ respectively as shown. The potential difference between points A (at a distance a from the first wire) and B (at a distance b from the second wire) is

• A. $\frac{\lambda}{2 \pi\varepsilon_{0}} ln \left(\frac{\left(d-a\right)\left(d-b\right)}{ab}\right)$
• B. $\frac{\lambda}{2 \pi\varepsilon_{0}} ln \left(\frac{d^2}{ab}\right)$
• C. $\frac{\lambda}{4 \pi\varepsilon_{0}} ln \left(\frac{\left(d-a\right)\left(d-b\right)}{ab}\right)$
• D. $\frac{\lambda}{2 \pi\varepsilon_{0}} \left(\frac{\left(d-a\right)\left(d-b\right)}{ab}\right)$

Answer 1

Answer: (D)

$\frac{\lambda}{2 \pi\varepsilon_{0}} \left(\frac{\left(d-a\right)\left(d-b\right)}{ab}\right)$

Answer 2

Electric force at a point due to a linear charge distribution is given by