The energy of an X-ray quantum of wavelength 1.0 x 10^-10 m is:
Correct answer: A. 1.99 x 10^-15 J
- A. 1.99 x 10^-15 J
- B. 3 x 10^8 J
- C. 6.6 x 10^-34 J
- D. 19.89 x 10^-26 J
- E. 1.99 J
Explanation
->v=fλ3 x 108=f x (1.0 X 10-10)f=3 x 108/1.0 X 10-10=3 x 1018->E=hfE=(6.62607004 × 10-34 )*(3 x 1018)=1.99 x 10-15
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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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