1. Electricity and Magnetism Test Review

2. DEFINE
These are in the book, go for it.

3. What does each variable stand for and what are the units?
What is Ohm's Law?
What does each variable stand for and what are the units?
Write the triangle for Ohm's Law
Give the 3 versions of Ohm's Law (Equation when solving for voltage? current? resistance?)
The relationship between current, resistance and voltage within a circuit.
I= Current (Amps), V= Voltage (v), R= Resistance (Ω)
I=V/R V=IR R=V/I

4. According to Ohm's law, which would require the greater voltage to move the current; 10 ohms resistance or 20 ohms resistance? Why?
The 20 Ω resistor would require more voltage to overcome the resistance

5. List the differences between series and parallel circuits (Refer to your T-chart)
Draw a Picture
Draw a picture
Remove a light bulb, the rest go out
Remove a light bulb, the remaining bulbs stay lit
Total resistance is added together
Resistance is not added together
Current stays the same
Voltage is the same, current is different through each branch depending on the resistance
Ex: Christmas lights
Ex: Household lights

6. What type of electricity does not require a wire
What type of electricity does not require a wire? Give 2 examples of this type of electricity.
Which subatomic particles move within the wire?
What is the standard voltage in a home?
Static electricity. Examples are lightning, rubbing feet against carpet
Electrons
120 V

7. What is alternating current?
What is direct current?
Give 3 examples of things that use AC
Current that changes direction over a set period of time.
Commonly multiple times a second.
Current that flows only in one direction. It is DIRECT.
Washing machine, refrigerator, microwave

8. Give 3 examples of things that use DC.
What is an AC/DC adapter?
What direction does current flow?
Anything that has an internal battery such as phones, tvs, flashlights.
Converts alternating current (which is the current inside your walls) into direct current to be used by something with a battery such as when you plug your phone into the wall.
Current flows from high to low.

10. What is the equation for Power?
What is the difference between a wet cell battery and a dry cell battery? Give an example of each.
What is the equation for Power?
What is the equation for Electrical Energy?
A dry cell battery has an electrolyte paste that electrons can flow through. These
Are small batteries like AA and AAA. A wet cell battery has a liquid electrolyte that
The electrons flow through. These are bigger batteries like car batteries.
P= IV so Power= Current x Voltage
E=Pt so Energy = Power x time

11. Name 3 good conductors.
Name 3 good insulators.
What makes a material a good conductor?
What makes a material a good insulator?
Copper, steel, brass, cast iron
Styrofoam, wood and rubber
Good conductors allow electrons to move freely, so electricity flows
through these objects.
An insulator does not allow electrons to flow freely.

12. If two materials of opposite charge are brought together what happens?
If 2 opposite charges are placed together, they will attract.
If 2 of the same charges are placed together, they will repel.

13. DEFINE
These are also in the book, go for it.

14. Name 3 magnetic materials and 3 nonmagnetic materials.
What are the two ends of a magnet called?
What happens when a magnet is broken in half?
Magnetic materials = Iron, Nickel and steel
Non magnetic materials = Plastic, stainless steel, and paper
Poles. There is a North pole and a South pole.
There are 2 separate magnets created. Both have a North AND South pole

15. What small shavings are typically used to show magnetic fields?
The South pole of a magnet should be attracted to which end of Earth?
What is an electromagnet?
Iron filings
The North pole because opposites attract
A type of magnet in which magnetic field is produced by an electric current

16. What 2 things will control how strongly two magnets are attracted or repelled?
What is a galvanometer?
If a circuit has a voltage of 45 V and a current of 5.0 A, what is the resistance?
Strength of the individual magnets and distance between the magnets
An instrument that detects electric current.
R=V/I
R= 45V/5A
R= 9 Ω

17. In this circuit, there is a resistance of 40 Ω and a current of 0
In this circuit, there is a resistance of 40 Ω and a current of 0.15 A, what is the voltage?
If a circuit has a voltage of 500 V and a resistance of 250 Ω, what is the current?
V = IR
V = .15A x 40Ω
V = 6 v
I = V/R
I = 500v/250Ω
I = 2A

18. If a circuit has a voltage of 400 V and a resistance of 80 Ω, what is the current?
In a circuit, there is a resistance of 400 Ω and a current of 0.01 A, what is the voltage?
I = V/R
I = 400v/80Ω
I = 5A
V = IR
V = .01A x 400Ω
V = 4 v

19. If a small appliance is rated at a current of 10 amps and a voltage of 120 volts, what is the power rating?
If a blender is plugged into a 110 V outlet that supplies 2.7 A of current, what amount of power is used by the blender?
P = IV
P = 10 A x 120 v
P = 1200 watts OR 1.2 kilowatts
P = IV
P = 2.7 A x 110 v
P = 297 watts OR .297 kilowatts

20. A motor is connected to a 12-V battery with a current of 1.5 A
How much power is delivered to the motor?
b. How much energy is transformed if the motor runs for 15 min?
P = IV
P = 1.5 A x 12 v
P = 18 watts OR .018 kilowatts
E = Pt
E = .018 kW x .25 hr
E = kWhr