Question

Two charges q1 = 4microC and q2 = -7 microC by 3.5m and 1.5m. Calculate the electric potential at point B having a distance of 2m.

Answer 1

Assuming that the charges lie on the x-axis, and the distances given are from origin,

Potential at B due to q₁

$V_1=k\frac{q}{r}$

$r_1= 3.5-2= 1.5m$

$V_1=\frac{9×10^9×4×10^{-6}}{1.5}=24000V$

$r_2= 2-1.5=0.5m$

$V_2 =\frac{9×10^9×-7×10^{-6}}{0.5}=-126000V$

Electric potential at B

$=-126000+24000=-102000V$