A uniform electric field of magnitude 339 N/C is directed along the +y-axis. A 6.00 µC charge moves from the origin to the point (x, y) = (-40 cm, -33 cm).What is the change in potential energy associated with this charge ?
Equipotentials are perpendicular to the electric fiels lines and directed along x-axis.
Since E= -grad φ, for 1D case:
E = Δφ/Δy.
Δ φ = E•Δy =339•0.33 = 112 V,
ΔPE = Work = q•Δ φ =(600•10^-6)•112 =
= 6.7•10^-2 J.