- A lot of this section is about the simple circuit but we will also tackle difficult ones. Difficult problems can often be split into simple steps.
- What is the difference between EMF and PD?
- Why is charge positive and negative?
- How are magnetic and electric fields similar and how are the different?
- How does an electric motor work?
Why is the North pole actually a South? Why do we define magnetic field in terms of rotation not acceleration? What is the connection between magnetic fields and electric current? Why don't magnetic waves exist without electric waves?
Electric force can not be explained without introducing a new quantity charge. You might think that this should be a fundamental quantity but it isn't, the fundamental unit of electricity is current. As with gravitational fields, field lines are used to
It's not often that you can impress your friends with your knowledge of physics but when the Northern lights appear everyone wants to know how they are formed.
Field lines not only show the direction of the force experienced by a small test charge but also the size. When drawing field lines make sure they start on a + and end on a -. Draw them carefully or you will throw away marks.
Magnetic fields are defined in terms of the rotation of a small magnetic dipole, this makes them quite different to electric and gravitational fields.
Not all circuits are this simple but a lot can be broken down into components that are.