An electric field of `20 N//C` exists along the x-axis in space. Calculate the potential difference `V_B - V_A` where the points A and B are given by
a. `A=(0,0), B=(4m, 2m)`
b. `A=(4m,2m),B=(6m,5m)`

Answer

`-80 V ; -40 V

Explanation

As the electric field is along X-axis, therefore, from `E = -dV//dr`
(i) `dV = -E (dr) = - E (x_(2) - x_(1))`
`= -20 (4-0) = -80V`
(ii) `dV = -20 (x'_(2) - x'_(1)) = -20 (6-4) = -40V`