Ohms Law

Ohms law is the relationship between Voltage and Current. Click here to learn more

Ohms law Practice questions

  1. What is the current in a circuit with a resistance of 5 ohms and a voltage of 10 volts?

  2. If a circuit has a current of 2 amps and a resistance of 4 ohms, what is the voltage?

  3. A circuit has a voltage of 12 volts and a current of 3 amps. What is the resistance of the circuit?

  4. If a circuit has a voltage of 6 volts and a resistance of 2 ohms, what is the current?

  5. A circuit has a resistance of 10 ohms and a current of 5 amps. What is the voltage?

  6. If a circuit has a voltage of 20 volts and a current of 5 amps, what is the resistance of the circuit?

  7. If a circuit has a voltage of 18 volts and a resistance of 3 ohms, what is the current?

  8. A circuit has a current of 1.5 amps and a voltage of 9 volts. What is the resistance of the circuit?

  9. If a circuit has a resistance of 20 ohms and a current of 0.5 amps, what is the voltage?

  10. A circuit has a voltage of 24 volts and a current of 2 amps. What is the resistance of the circuit?


Answers to above questions

  1. The current in the circuit is 2 amps (I = V/R = 10/5).
  2. The voltage in the circuit is 8 volts (V = I x R = 2 x 4).
  3. The resistance of the circuit is 4 ohms (R = V/I = 12/3).
  4. The current in the circuit is 3 amps (I = V/R = 6/2).
  5. The voltage in the circuit is 50 volts (V = I x R = 10 x 5).
  6. The resistance of the circuit is 4 ohms (R = V/I = 20/5).
  7. The current in the circuit is 6 amps (I = V/R = 18/3).
  8. The resistance of the circuit is 6 ohms (R = V/I = 9/1.5).
  9. The voltage in the circuit is 10 volts (V = I x R = 0.5 x 20).
  10. The power of the circuit is 12 ohms (R = V/I = 24/2).

References: ChatGPT

Measuring Ohms law, Series and Parallel Circuits

Using the mathematics behind ohms law we can try to measure the difference between Series and Parallel Circuits and how energy is distributed throughout the circuit.
Can be done on Electricity DC Phet Simulations if needed, be sure to select “real light globes”.

Aim

To determine the resistance of a light in different circuits using Ohms law

Setup

  • Draw up a table with Volts across the top (2-12) and open rows for the different setups
  • Setup a simple series circuit, with the Ammeter in series and Voltmeter in parallel
  • Scan through the power pack from 2V to 12 V, recording the Amps measured in the table row
  • Retest with 2 light bulbs in the same series circuit, filling in the next row on your table
  • (IF POSSIBLE) Retest with 3 lights in same series circuit, filling in next row on your table
  • Reset your setup and make a parallel circuit with 2 lights, (your Ammeter is going to be shifted around)
  • Put the Ammeter in series with the power pack and first light bulb (should measure the current from both bulbs), record on table
  • Next, move the Ammeter to the bulb only, record on table
  • (IF POSSIBLE) Retest with a 3rd bulb and include results on table.
Setup/Voltage2V (A)4V (A)6V (A)8V (A)10V (A)12V (A)
Series 1 bulb
Series 2 bulb
Series 3 bulb
Parallel both bulbs
Parallel single bulb
Parallel 3 bulbs

Observations/ Discussion

  • Using Ohms Law, calculate if the resistance of the light bulb remained constant, or changed with the setup and voltage
    NOTE: this will require you to look at your results table and apply R= V/I
  • Did the light bulb follow Ohms law in any scenario?
  • The more lights you added, did it impact your resistance calculations?
  • Did the resistance change more or less in a parallel circuit?
  • BONUS: graph your data to see how the line trends as voltage is increased