AP Physics C: Electricity and Magnetism Practice Quiz: Electric Power
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Test your understanding with short quizzes. This quiz has 9 questions to check your progress.
Question 1 of 9
All Questions (9)
A) Current
B) Voltage
C) Resistance
D) Power
Correct Answer: D
Based on the provided content, power is defined as the rate at which energy is transferred, converted, or dissipated within an electric circuit.
A) 6.0 W
B) 14 W
C) 24 W
D) 0.17 W
Correct Answer: C
Using the equation for electric power, P = IΔV. Substituting the given values: P = (2.0 A)(12 V) = 24 W.
A) 2.0 W
B) 50 W
C) 100 W
D) 250 W
Correct Answer: D
The rate of energy dissipation is power. Using the derived equation P = I²R: P = (5.0 A)²(10 Ω) = (25 A²)(10 Ω) = 250 W.
A) 0.5 W
B) 2.0 W
C) 120 W
D) 1800 W
Correct Answer: C
To find the power consumption, we can use the derived equation P = (ΔV)²/R. Substituting the values: P = (60 V)² / 30 Ω = 3600 V² / 30 Ω = 120 W.
A) It will be half as bright.
B) It will be twice as bright.
C) It will be four times as bright.
D) Its brightness will not change.
Correct Answer: C
Power is related to potential difference by the equation P = (ΔV)²/R. If ΔV is doubled, the new power will be (2ΔV)²/R = 4(ΔV)²/R, which is four times the original power. Therefore, the bulb will be four times as bright.
A) P/9
B) P/3
C) 3P
D) 9P
Correct Answer: A
According to the equation P = I²R, power is proportional to the square of the current. If the current becomes I/3, the new power will be (I/3)²R = (I²/9)R = (1/9)I²R = P/9.
A) The battery dissipates energy at a rate of P = IΔV, and the lightbulb transfers this energy into light and heat.
B) The battery supplies energy at a rate P = IΔV, which is then transferred into light and thermal energy by the lightbulb.
C) The lightbulb creates energy at a rate of P = I²R, which is supplied by the current from the battery.
D) Energy is transferred from the current to the battery at a rate P = IΔV and then dissipated by the lightbulb.
Correct Answer: B
Power describes the rate of energy transfer. The battery is the source of energy, supplying it at a rate P = IΔV. The lightbulb is a circuit element that converts or dissipates this electrical energy into other forms, such as light and thermal energy.
A) Bulb A is brighter because it has a higher resistance.
B) Bulb B is brighter because it has a lower resistance.
C) Both bulbs have the same brightness because they have the same potential difference.
D) Their relative brightness cannot be determined without knowing the current.
Correct Answer: B
When connected in parallel, both bulbs have the same potential difference (ΔV) across them. The brightness depends on power, and the relevant equation is P = (ΔV)²/R. Since power is inversely proportional to resistance at a constant voltage, the bulb with the lower resistance (Bulb B) will dissipate more power and be brighter.
A) Bulb X is brighter because it has a higher resistance.
B) Bulb Y is brighter because it has a lower resistance.
C) Both bulbs have the same brightness because the same current flows through them.
D) Bulb Y is brighter because it has a smaller potential difference across it.
Correct Answer: A
When connected in series, the same current (I) flows through both bulbs. The brightness depends on power, and the relevant equation is P = I²R. Since power is directly proportional to resistance for a constant current, the bulb with the greater resistance (Bulb X) will dissipate more power and be brighter.