Download PROBLEM SET AP1 Ohms Law, Power, and Energy

AP® Physics 1
Myers Park High School
Problem Set: Ohm’s Law, Power, and Energy
Solve the following problems. Answers are given at the end of the problem set.
1. (I) A resistance of 30 Ω is placed across a 90 V battery. What current flows?
2. (I) A motor with an operating resistance of 30 Ω is connected to a voltage source. The
current in the motor is 4.0 A. What is the voltage of the source?
3. (I) A transistor radio uses 0.2 A of current when it is operated by a 3 V battery. What is
the resistance of the radio?
4. (I) A current of 0.5 A flows through a lamp when it is connected to a 120 V source.
a. What is the resistance of the lamp?
b. What is the wattage of the lamp?
5. (II) A TV connected to a 120 V outlet consumes 85 W of power.
a. How much current flows through the TV?
b. How long does it take 10 million electrons to pass through the TV?
6. (I) A copper wire (Resistivity 1.68 x 10-8 Ω*m) is 5 miles long and 0.50 mm in diameter.
What is its resistance?
7. (II) A current of 0.76 A flows through a copper wire 0.44 mm in diameter when it is
connected to a potential difference of 15 V. What is the length of the wire?
8. (II) When a potential difference of 12 V is applied to a wire 6.9 m long and 0.33 mm in
diameter the result is an electric current of 2.1 A. What is the resistivity of the wire?
9. (II) A battery with an emf of 12 V is connected to a 545 Ω resistor. How much energy is
dissipated in the resistor in 65 s?
10. (II) A holiday goose is cooked in the kitchen oven for 4.00 hours. Assume that the oven
draws a current of 20.0 A, operates at a voltage of 220 V, and uses electrical energy that
costs $0.048 per kW/h. How much does it cost to cook your goose?
1) 3 A
5) a. 0.708A
b.
9) 17.2 J
2) 120 V
6) 700 Ω
10) $0.84
3) 15 Ω
7) 170 m
4) a. 240 Ω b. 60 W
8) 7.1 x 10-8 Ω*m