1. Who Killed the Electric Car?
Video from Friday
Worksheet due on Tuesday

2. Topic 6,7,8 Test Wednesday April 22nd
Multiple Choice
Written Response
Topic 6: everything including drawing diagrams of generators and motors
Topic 7: everything including full response math questions (formula, substitute, solve)
Bring your calculator!
Topic 8: everything including higher-order thinking attitudes

3. Topic 7: From the Grid to Your Home
Residential
Step down
Transformer
Substation:
Step up
Transformer
Distribution
Station

4. Investigation Page 334 in your textbook How efficient is coal, really?
Topic 8
Investigation
Page 334 in your textbook
How efficient is coal, really?
Calculate the percent of energy from coal that ends up giving you light from an incandescent bulb
Start with 1 million joules = 1 x 106 = J
99% x 97% x 33 % x 85% x 15%

5. What is more efficient, really?
Topic 8
What is more efficient, really?
Incandescent light bulbs
Fluorescent light bulbs
Take notes on the 12 minute video because you will be asked a related question on your test.

6. REVIEW E = P x t is the formula on your PAT Be able to use it for
Joules = Watts x sec
kWh = kilowatts x hours
P = E/t
t = E/P
P = I x V is the formula on your PAT
Be able to manipulate it for:
I = P/V
V = P/I

7. Calculate power
P = I x V
What is the power, in Watts, of an electronic device that allows 3 A of current when plugged into a 120V socket?

8. Calculate power Answer
What is the power, in Watts, of an electronic device that allows 3 A of current when plugged into a 120V socket?
P = I x V
P = 3A x 120V
P = 360 W

9. Find Current
What is the current in an 80 W light bulb in a 120V socket?
P = I x V

10. Find Current Answer
What is the current in an 80 W light bulb in a 120V socket?
P = I x V
P/V = I x V/V
I = P ÷ V
I = 80 W ÷ 120 V
I = 0.67 A

11. Find Voltage
What is the voltage of a 110 W device with 4A?
P = I x V

12. Find Voltage Answer What is the voltage of a 110 W device with 4A?
P = I x V
P/I = I x V / I
V = P ÷ I
V = 110 W ÷ 4 A
V = 27.5 V

13. Calculate energy E = P x t
What is the energy input, in Joules, of a 60 W laptop charger that is plugged in for 45 minutes?

14. Calculate energy Answer
E = P x t
What is the energy input, in Joules, of a 60 W laptop charger that is plugged in for 45 minutes?
E = P x t t = 45 x 60 = 2700 s
E = 60W x 2700s
E = 162,000 J

15. Calculate Efficiency Charger
The 60 W laptop charger that is plugged in for 45 minutes outputs 98,000 J of useful energy to the laptop battery. How efficient is this charger?

16. Calculate Efficiency Answer
The 60 W laptop charger that is plugged in for 45 minutes outputs 98,000 J of useful energy to the laptop battery. How efficient is this charger? E = P x t
E = 60 W x (45x60) seconds
E = 162,000 J
Efficiency = output/input x 100%
Efficiency = 98,000 J x 100%
162,000 J
Efficiency = 60.5 %

17. Calculate Efficiency Lightbulb
A 45 W lightbulb that is on for 90 minutes outputs 98,000 J of light energy. How efficient is this bulb?

18. Calculate Efficiency Answer
A 45 W lightbulb that is on for 90 minutes outputs 98,000 J of light energy. How efficient is this bulb? E = P x t
E = 45 W x (90x60) seconds
E = 243,000 J
Efficiency = output/input x 100%
Efficiency = 20,000 J x 100%
243,000 J
Efficiency = 8 %