The energy of a photon is given by
Correct answer: A. hf
- A. hf
- B. h divided by f
- C. hc
- D. mc squared only
Explanation
Energy is Planck's constant multiplied by frequency, equivalently hc divided by wavelength, so shorter wavelength means more energetic photons. This is why ultraviolet light damages skin while visible light of the same intensity does not. Planck's constant is 6.63 times 10 to the minus 34 joule seconds.
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About Quantum Theory and Radiation
Quantum theory treats electromagnetic radiation as packets of energy called photons, with energy proportional to frequency through E equals hf. The topic covers Planck's hypothesis, photon momentum, the photoelectric effect, threshold frequency, work function and wave particle duality, distinguishing quantised energy exchange from classical continuous radiation.
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