Ohm’s Law Worksheet
Solve each problem in the space provided. Be sure to show all of your work including placing units on all numbers. Round your answers to two decimal places where necessary.
1. A circuit has a resistance of 3.7 Ω. Find the voltage needed to produce a current of 4.0 A in the circuit.
2. How much current will flow through a lamp that has a resistance of 60 Ω when a voltage of 12 V is applied?
3. What is the resistance of an electric frying pan that draws 12 A of current when connected to a 120V circuit?
4. A current of 6.25 A flows through a microwave oven. If the resistance of the circuit in the oven is 17.6 Ω, what is the potential difference across the oven?
5. A hair dryer draws 8.33 A of electric current when it is connected to a 110 V line. What is the resistance of the heating coil in the hair dryer?
6. How much current will flow through a circuit that has a resistance of 25 Ω and a 4.5 V battery power supply?
7. A motor with an operating resistance of 32 Ω is connected to a voltage source. The current is 3.8 A. What is the voltage of the source?
8. An automobile headlight with a resistance of 30 Ω is placed across a 12 V battery. What is the current through the circuit?
9. Currents above 0.005 A are painful to humans and values above 0.010 A can cause muscle spasms. The resistance of a person with dry skin is approximately 100,000 Ω. If you touch the terminals of a 12 V battery with dry skin, how much current will flow through your body? Will this be enough to be painful? (Make sure your answer has at least two numbers other than zero in it.)
10. Consider the situation in question #7 again. This time you touch the 12 V battery with wet skin. The resistance of a person with wet skin is approximately 1000 Ω. How much current will you receive now? Will this be painful or cause muscle spasms?