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Total Cost. Number of kWh. The Cost of Electricity. Cost per kWh. $ TOTAL = N kWh ∙$ kWh. The electric company charges you for the amount of ENERGY they provide to you. Energy provided is “Work” Measured in strange unit: “ KiloWatt -Hours” $0.0776 per kWh in NoVA
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Total Cost Number of kWh The Cost of Electricity Cost per kWh $TOTAL = N kWh ∙$kWh • The electric company charges you for the amount of ENERGY they provide to you. • Energy provided is “Work” • Measured in strange unit: “KiloWatt-Hours” • $0.0776 per kWh in NoVA • Household Electric Sockets operate at 120 V • Heavy equipment outlets (welders, clothes dryers, ovens, etc) operate at 240 V
Warm-Up #1 • A toaster has a resistance of 4.0 Ω. • How much current does the toaster draw from your house’s 120 V power outlet? • How much power does the lighter use? • How much does it cost to run the toaster for one minute a day, all month?
Warm-Up #2 • A 120 V outlet in Paulina’s college dorm room is wired with a circuit breaker on a 5 A line so that students cannot overload the circuit. • If Paulina tries to iron a blouse for class with a 700 W iron, will she trip the circuit breaker? • What is the resistance of the Iron?