# Magnitude of force, potential energy for an electron, directions for the magnetic field, generator vs motor

1.

Four charges are arranged on a rectangle with sides of 2 cm and 5 cm respectively as shown in the figure. What is the magnitude of the force on Q3 ?

Q1= 8mC Q2= -7mC

Q3= 9mC Q4= -7mC

2.

There are three large charged parallel planes with charge per unit area (charge density) of sigma1 = -8 x 10-9 C/m2, sigma2 = -8 x 10-9 C/m2, sigma3 = -2 x 10-9 C/m2. Point X is located between the first and second plate and point Y is located between the second and third plate.

1.

Which has the higher potential energy for an electron? (Explain)

2.

Which has the higher electrical potential for an electron? (Explain)

3.

An electron travels in a horizontal (x-y) plane and experiences a force in the vertical (z) direction due to a uniform magnetic field. (The force can be up or down.) Which are the possible directions for the magnetic field? Explain using the right hand rule.

4.

Briefly explain the relationship between an electric generator and an electric motor. Be sure to outline their basic operation.

https://brainmass.com/physics/right-hand-rule/42810

#### Solution Summary

In four pages of handwritten calculations, the answers are fully explained including diagrams.