Which best describes the photoelectric effect?

• A. A metal emits electrons when light of a certain frequency shines on it.
• B. Classical mechanics failed to predict the radiation given off by blackbodies.
• C. An electron is emitted by a metal after enough photons have been absorbed.
• D. Waves cancel each other out or build each other up.
• E. None of the above accurately describes the photoelectric effect.

Answer: (A)

Verified step by step guidance

1. Understand the photoelectric effect: It is a phenomenon where electrons are emitted from a material, typically a metal, when it is exposed to light of a certain frequency.
2. Recognize the key aspect of the photoelectric effect: The emission of electrons is dependent on the frequency of the incident light, not the intensity. This means that only light above a certain threshold frequency can cause electron emission.
3. Classical mechanics prediction: Classical physics could not explain why light below a certain frequency, regardless of its intensity, would not cause electron emission. This was one of the failures of classical mechanics in explaining the behavior of blackbody radiation.
4. Photon absorption: In the photoelectric effect, electrons are emitted when individual photons with sufficient energy (related to frequency) strike the metal surface. This is not about accumulating energy from multiple photons.
5. Wave interference: The photoelectric effect is not related to wave interference, where waves can cancel each other out or amplify each other. It is specifically about the interaction between photons and electrons in a material.