Which of the following has the largest energy?
Correct answer: C. A photon of wavelength 2 pm
- A. A photon of wavelength 1nm
- B. A photon of wavelength 50 μm
- C. A photon of wavelength 2 pm
- D. A photon of wavelength 200 nm
Explanation
A photon of wavelength 2 pmExplanation:The energy (E) of a photon is related to its wavelength (λ) by the equation: E = hc / λ, where h is Planck's constant and c is the speed of light.This equation shows that energy is inversely proportional to wavelength. Therefore, the shorter the wavelength, the higher the energy.We need to compare the wavelengths:1 nm = 1 × 10⁻⁹ m50 μm = 50 × 10⁻⁶ m2 pm = 2 × 10⁻¹² m200 nm = 200 × 10⁻⁹ m2 pm is the shortest wavelength, so it corresponds to the highest energy.
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About Dawn of Modern Physics
Classical physics cannot explain blackbody radiation and related observations, leading to Planck’s quantum theory, in which energy is emitted or absorbed in discrete packets. Photons provide the particle model of light, with energy and momentum linked to frequency and wavelength, including the photoelectric effect and its threshold frequency.
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