1. Two large metal plates are parallel to each other and separated by 2cm. They are connected to a 120V battery. Assume the plates are in vacuum and the dimensions of the plates are much, much larger than 2cm.
(a) Calculate the electric field between the plates.
(b) An electron starts from rest and moves from the negative plate to the positive plate across the gap between the plates. Calculate its change of potential energy.
(c) What is the speed of the electron just before it hits the positive plate?
2. A tin nucleus has 50 protons.
(a) Find the potential of the tin nucleus at a distance of 1.0 × 10−12m from it.
(b) If a free proton is released from rest from this distance, how fast will it be going when it is 1.0m from the nucleus?
3. What is the charge on a 300pF capacitor when it is charged to a voltage of 1.0kV ?
4. Four point charges are placed at the four corners of a square that is 30cm on each side. Find the potential at the center of the square if
(a) the four charges are each +2µC
(b) the top left and bottom right charges are +2µC, and the top right and bottom left are −2µC.