UNIT V STUDY GUIDE Electricity & Magnetism ANSWER KEY

1. Electricity is basically moving ____________. electrons

The opposition posed by a material to the flow of current. 2. What is resistance? The opposition posed by a material to the flow of current.

3. What are the two factors of a wire that determine resistance? Length Area (diameter) Additional factors – Temperature & Material Type.

4. Resistance is measure in what unit? Ohms (Ω)

5. A closed path that allows current to flow is called a __________. Circuit

6. Describe the difference between a parallel and series circuit?

7. What are examples of when you would use each type of circuit? Series – used for things with batteries. Parallel – used around the house; when things get their power from generators.

8. What is the name of a device used to prevent overheating of circuits? Resistor

9. What is AC? Alternating Current Electron direction is constantly flipping; electric field is changing directions.

Electrons flow & electric field is in one direction. 10. What is DC? Direct Current Electrons flow & electric field is in one direction.

11. Which (AC or DC) is a battery? DC (Direct Current)

12. What “makes” AC? Generators

Converts mechanical energy into electrical energy. 13. What does an electric motor do? (Hint: what form of energy does it start with and then convert to?) Converts mechanical energy into electrical energy.

Electrons are easiest because they are in the electron cloud. 14. What are the charges of electrons, protons, and neutrons? Why are electrons the easiest to “remove”? e- negative p+ positive n0 neutral Electrons are easiest because they are in the electron cloud.

15. What is the difference between conductors and insulators? Conductors allow the flow of electric current. Insulators resist the flow of electric current.

16. What is the definition of current? The rate at which charges move through a conductor.

17. What is the unit of current? Amperes / Amps (A)

18. What is the equation to calculate voltage? V = I·R

19. What is the voltage if the current is 10 amps and the resistance is 2 ohms? 20 volts

20. If 2 resistors are in series, what mathematical function must you use to determine the “equivalent resistance”? REQ = R1 + R2 + …

21. If one light goes and the others go out, what type of circuit do you have? Series

22. How can you induce current in a wire with a magnet? By moving the magnet back and forth (changing the electric field)

23. How would you make an electromagnet? By wrapping a wire supplied with current around an iron core.

24. Be able to draw series and parallel circuits. SERIES EXAMPLE: PARALLEL EXAMPLE: