1. Two metal plates are connected to a 9V battery with negligible internal resistance. If the plates are 10 cm apart, what is the electric field at either of the plates?
2. What is the electric field at the midpoint between the plates?
The whole point of a uniform electric field is that the field does not change anywhere between the plates - at the midpoint, as anywhere, it is 90 NC−1.
3. The charge on an electron is -1.6 x 10−19 C. What is the electric field 1μm from a hydrogen nucleus?
4. What is the direction of this field?
The hydrogen nucleus has a positive charge, so the electric field goes away from the nucleus (by convention).
5. A 2C charge is placed 1m from a -1C charge. At what point will the electric field be 0?
Define the distance r as shown: