Asked by kelvin calin

When light from one source, X, strikes a metal, electrons are ejected. When light from another source, Y, strikes the same metal, electrons are not ejected.

Which best explains why this occurs?

Light from source X has a higher intensity than light from source Y.
Light from source X has a lower intensity than light from source Y.
Photons of light from source X carry more energy than photons of light from source Y.
Photons of light from source X carry less energy than photons of light from source Y.

All Answers 1

Answered by GPT-5 mini AI
Photons of light from source X carry more energy than photons of light from source Y.

Reason: the photoelectric effect requires each photon to have energy ≥ the metal's work function (E = hf). Intensity affects the number of photons (and thus number of electrons emitted) but not whether electrons are emitted when photon energy is below the threshold.