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Ohm's Law Question Generator

V = IR, rearranged three ways, with values chosen so every answer is a whole number — because the difficulty in this topic is the rearrangement and the units, not the division. The stretch level chains into power, which is where the two-step questions live: find the voltage from Ohm's law, then the power from P = VI, and notice that P = I²R gets there in one.

What this generator does

Draws a current and a resistance as whole numbers, so the voltage is whole too, and asks for whichever quantity is missing. Power questions give the current and resistance and expect the chain through voltage, or the direct I²R route.

How to use this tool

  1. Choose how many questions you want and at what level.
  2. Identify which of V, I and R you have, and rearrange for the one you want.
  3. Reveal the answers to check the value and the unit.
  4. Show the working to see the rearrangement written out.

Understanding the controls

How many questions
Between 1 and 20. Twelve covers all three rearrangements several times over.
Level
Gentle asks only for voltage, with small values. Standard adds resistance questions, and stretch adds power, which is the two-step case.
Seed
Gives the same circuits again from a word you choose.
Show the answers / working
The value and its unit, or the rearrangement and substitution as well.

Common use cases

  • Drilling the three rearrangements of Ohm's law
  • Practice where the arithmetic never obscures the method
  • Introducing power as a second step rather than a fourth formula
  • Checking that units are carried through — volts, amps, ohms and watts
  • Giving a group the same questions from a seed

How this generator works

Current and resistance are drawn as whole numbers and the voltage follows as their product, which keeps every rearrangement exact. The check recomputes the asked-for quantity from the values the question actually states — including verifying that a resistance answer multiplied by the current returns the stated voltage.

Randomness and fairness

The circuit values and which quantity is asked for are random; the relationships are fixed. Seeded sets reproduce exactly and are therefore explicitly not cryptographically secure. Without a seed the browser's cryptographically secure generator is used.

For how randomness is produced across the whole site, see how Generate Random works.

Limitations and good to know

  • Single components only. Series and parallel combinations are not generated.
  • Values are whole numbers in base units, so milliamps and kilohms never appear.
  • Only the resistive case — capacitance, inductance and alternating current are out of scope.
  • Power questions always give current and resistance, so the P = V²/R route is not exercised.
  • Nothing is stored between visits; seed a set you want to reuse.

Privacy and your data

Circuit values are generated in your browser. Your seed and level are never transmitted and are not remembered between visits.

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