Who Killed the Electric Car Video from Friday

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

Topic 6, 7, 8 Test Wednesday April 22 nd • 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

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

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 = 1 000 J • 99% x 97% x 33 % x 85% x 15%

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. • https: //www. youtube. com/watch? v=3 gjv. OOl. Hms. U

REVIEW • E = P x t is the formula on your PAT • Be able to use it for – Joules = Watts x sec – k. Wh = 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

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

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

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

Find Current Answer • What is the current in an 80 W light bulb in a 120 V socket? • P=Ix. V • P/V = I x V/V • I=P÷V • I = 80 W ÷ 120 V • I = 0. 67 A

Find Voltage • What is the voltage of a 110 W device with 4 A? • P=Ix. V

Find Voltage Answer • What is the voltage of a 110 W device with 4 A? • P=Ix. V • P/I = I x V / I • V=P÷I • V = 110 W ÷ 4 A • V = 27. 5 V

Calculate energy • E=Pxt • What is the energy input, in Joules, of a 60 W laptop charger that is plugged in for 45 minutes?

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

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?

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=Pxt E = 60 W x (45 x 60) seconds E = 162, 000 J • Efficiency = output/input x 100% • Efficiency = 98, 000 J x 100% 162, 000 J • Efficiency = 60. 5 %

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?

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? seconds E=Pxt E = 45 W x (90 x 60) E = 243, 000 J • Efficiency = output/input x 100% • Efficiency = 20, 000 J x 100% 243, 000 J • Efficiency = 8 %