In a photoelectric effect monochromatic light is incident on a metal surface. If the incident light of twice the intensity but of same wavelength the kinetic energy of the emitted electron_______________?
Correct answer: B. Remains same
- A. Becomes double
- B. Remains same
- C. Becomes half
- D. First increases then decrease because of the curvilinear graph
Explanation
For the same wavelength, each photon has the same energy hf, so doubling intensity only increases the number of photons and emitted electrons per second. The maximum kinetic energy remains Kmax = hf - Φ and is therefore unchanged. The likely mistake is choosing a because greater intensity is incorrectly treated as greater energy per photon.
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About Photons and the Particle Model of Light
The particle model treats light as photons with energy E equals hf and momentum related to wavelength. Questions involve the photoelectric effect, work function, threshold frequency, stopping potential and photon energy, while distinguishing particle behaviour from the wave description of interference and diffraction.
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