Question 1 Multiple Choice
A toaster draws 10 A from a 120 V outlet. What is its power consumption?
A12 W
B130 W
C1,200 W
D1.2 W
P = IV = 10 A × 120 V = 1,200 W (or 1.2 kW).
Question 2 True / False
Doubling the current through a fixed resistor quadruples the power dissipated.
Answer: True
Using P = I²R, if current doubles then power = (2I)²R = 4I²R, which is four times the original power.
Question 3 Short Answer
A 60 W light bulb is on for 2 hours. How much energy does it use in kilowatt-hours?
Think about your answer, then reveal below.
Model answer: 0.12 kWh, because 60 W = 0.06 kW, and 0.06 kW × 2 hours = 0.12 kWh.
Convert watts to kilowatts (60/1000 = 0.06 kW), then multiply by time in hours: 0.06 × 2 = 0.12 kWh.