A uniform electric field has magnitude E and is directed in the negative x-direction. The potential difference between point a (at x = 0.60 m) and point b (at x = 0.90 m) is 240 V. (a) Which point, a or b, is at the higher potential? (b) Calculate the value of E. (c) A negative point charge q = -0.200 µC is moved from b to a. Calculate the work done on the point charge by the electric field.

Introduction First we have to discuss which point has higher potential, then we have to calculate the value of electric field and then we have to work done to move negative point charge of given magnitude from b to a. Step 1 The electric field is directed from higher to lower potential. Since the the electric field directed towards the negative x direction, value of the potential will be higher for the points having greater positive value of x. Hence x = 0.900 m has higher potential.