Examine the diagram of the electric bell. Use the principles of electromagnetism to explain why the hammer hits the bell when the switch is closed. Hammer Contacts Electromagnet Battery E Switch Task 4: Electricity and Magnetism Knowledge Choose four of the following five questions to answer. 1. Explain the difference between AC and DC current. 2. List two types of elements that would cause an electric potential drop in a circuit and one type of element that would cause an electric potential gain in a circuit. 3. Which type of circuits contains junctions? Explain what happens to the current at a junction. 4 List one similarity and one difference of electric and magnetic fields. 5. List one part of a DC motor that you could change that would reverse the direction of rotation of the motor.