Halliday, Resnick & Walker — Electric Potential: Problem 12

12 The electric potential V in the space between two flat parallel plates 1 and 2 is given (in volts) by \(V = 1500x^2\), where \(x\) (in meters) is the perpendicular distance from plate 1. At \(x = 1.8 \text{ cm}\), (a) what is the magnitude of the electric field and (b) is the field directed toward or away from plate 1?