Wave and photon models of lightEdexcel International A Level Physics: Flashcards
What these 12 flashcards ask
- What does the wave model of light explain?
- What does the photon model say?
- State the equation for photon energy.
- Write E in terms of wavelength.
- What is the value of the Planck constant?
- Which experiment showed light behaves as a wave?
- Who proposed the particle (corpuscular) model of light?
- Who explained the photoelectric effect using photons?
- What happens to photon energy if frequency doubles?
- What does a brighter beam of the same frequency mean?
- How do you find the number of photons emitted per second?
- Why do radio waves behave as waves rather than as photons?
Exam questions on Wave and photon models of light
- A teacher is comparing the wave model and the photon model of light. She demonstrates Young's double-slit experiment with a laser and then discusses how light is emitted and absorbed by atoms.Explain why a particle model of light cannot account for the fringes observed in the double-slit experiment.2 marks
- A laser pointer emits red light of wavelength 650 nm. A second laser pointer emits green light of wavelength 532 nm with the same power output. Use the Planck constant h = 6.63 × 10⁻³⁴ J s and the speed of light c = 3.00 × 10⁸ m s⁻¹.Calculate the energy of one photon from the red laser pointer.2 marks
- A sodium street lamp emits yellow light of wavelength 589 nm. The power emitted by the lamp as light is 20 W. Use the Planck constant h = 6.63 × 10⁻³⁴ J s and the speed of light c = 3.00 × 10⁸ m s⁻¹.Calculate the energy of one photon emitted by the lamp.3 marks
Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).