The correct answer: (b) light with any intensity above a certain frequency
The explanation:
when Energy of a photon : E = hf
- The photoelectric effect works like this:
- If you shine light of high enough energy on to a metal, electrons will be emitted from the metal. Light below a certain threshold frequency, no matter how intense, will not cause any electrons to be emitted. Light above the threshold frequency, even if it's not very intense, will always cause electrons to be emitted.