Exam-style question
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What is the momentum of a photon with a wavelength of 500 nm?.
- A.3.99 x 10^-27 kg m/s
- B.4.14 x 10^-22 kg m/s
- C.1.24 x 10^-24 kg m/s
- D.6.63 x 10^-34 kg m/s
Model answer
What a good answer should say
- 4.14 x 10^-22 kg m/s
Explanation
Why this works
The momentum (p) of a photon can be calculated using p = h / λ. Substituting h = 6.63 x 10^-34 J s and λ = 500 nm (5 x 10^-7 m), we get p = 6.63 x 10^-34 J s / (5 x 10^-7 m) = 4.14 x 10^-22 kg m/s.
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