Electricity and Magnetism Answers

a) Two identical charges q₁ and q₂ make up a system with a potential energy of 1590J when the distance between them is 0.4m. Find the magnitude of the charges q₁ and q₂.

a) Find the distance at which you need to place a charge -16 x10^-6C from a charge 10 x10^-9C such that the potential energy between them is equal to 9x10^-5J.

b) Find the potential energy of a system of a charge of +7 x10^-6C is found at 0.06m of another charge of 20 x10^-6C?

a) Calculate the potential energy of a charge +6nC placed at 0.07m from a charge +76 x10^-6C. If the same charge if at 0.07m from a charge -88 x10^-6C, find its potential energy.

b) Find the distance from a charge -8 x10^-6C to a charge -4 x10^-9C if there is a potential energy of 9.5kJ between them. Find the initial force on charge -4 x10^-9C.

Two charges (+3µC on the left of the -5µC) are separated by a distance of 5um on a horizontal line. Point P is located 10µm above the 3µC charge.

a) Draw a sketch of the setting discussed in the question above. Make sure to label all points discussed. (2marks)

b) Calculate the field at point P (3marks)

c) Calculate the potential at point P 

(1 mark)

Find the electric potential at a point located at 0.05m of a charge of +8x10^-6C. Find the potential energy of a charge of 3x10^-9C that is located at that same point.

How many excess electrons must be added to a plastic solid sphere that has a diameter of 0.26 m to produce an electric field of 1030 N/C at the edge of the surface? Assuming the charge is uniform, what is the electric field at 10 cm from the center?

Static electricity can be used to paint a car door.

Decide if the following statements are true or

false.

1. the paint nozzle is connected to the positive

terminal.

2. this makes the paint drops have zero charge.

3. The paint drops repel each other.

4. The drops sticks together.

5. The car door has a negative charge.

6. The paint drops are attracted to the car door.