# Help Electric field and Potential

Electric Field and Potential

help me in answering these questions. sorry guys, not really good at physics.. thanks for the BIG help!

a)Two large metal sheets carrying equal and opposite electric charged are separated by a distance of 52.0 mm. The electric field between them is uniform and has a magnitude of 670 N/C.
i)What is the potential difference between the sheets?
ii)Which sheet is at higher potential, the one with positive charge or the one with negative charge?

b)A proton of charge q=1.60x10-19 C is placed in a region of uniform electric field with field strength E=1.46x105 N/C. What is the electrostatic force on the proton?

c)Three equal positive point charges of magnitude Q are located at three corners of a square of edge length d. A negative charge –3Q is placed on the fourth corner. At the position of the negative charge, what is the magnitude of the electric field due to the three positive charges? What is the force on the negative charge?

d)Four equal point charges of magnitude Q are arranged on the corners of a square of edge length 1.0 cm. Evaluate the electric field at the center and the midpoint of one edge, given that Q=1.0x10-9 C.