What quantity did you change?
Labs / Physics
Photoelectric Effect
Aim a beam of coloured light at a metal plate and sweep its frequency by dragging across the canvas. Electrons only leap free once each photon carries more energy than the metal's work function — turning the brightness up never helps if the colour is too red. Adjust the intensity, swap metals, and dial in a stopping voltage to measure how fast the electrons come off.
Labs / Physics / Photoelectric Effect
Photoelectric Effect
Aim a beam of coloured light at a metal plate and sweep its frequency by dragging across the canvas. Electrons only leap free once each photon carries more energy than the metal's work function — turning the brightness up never helps if the colour is too red. Adjust the intensity, swap metals, and dial in a stopping voltage to measure how fast the electrons come off.
Why it matters
Why explore this?
Physics explains how changes in forces, energy, motion, and matter produce results we can measure. This model lets you test one part of that relationship at a time.
Explore
Try the model
Ephoton 4.96 eVW 2.28 eVKEmax 2.68 eVI 0 e⁻/s
Investigate
Questions to test
Predict first, try it in the model, then use what you observe to answer.
What to try
- Crank the intensity to 100% on red light. Why does a blindingly bright red beam still eject no electrons?
- Slowly raise the frequency on cesium. At what photon energy do the first electrons suddenly appear?
- Switch from cesium to platinum without touching the colour. Where did all the electrons go?
- With electrons flying, raise the stopping voltage. What value just barely stops the fastest ones — and how does that compare to the max kinetic energy?
- Does more intensity change how fast each electron leaves, or only how many leave per second?
Explain
Make sense of what happened
Name the quantity you changed, the quantity that responded, and the physical rule connecting them. Use a readout or visible change as evidence.
Check
Before you leave
What measurable result changed?
Which physical idea connects them?
If you can answer all three using evidence from the model, you understand the main idea. If not, return to Explore and change one setting at a time.