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Q132 (IAS/2008) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Waves and acoustics Answer Verified

Assertion (A) : In the visible spectrum of light, red light is more energetic than green light. Reason (R) : The wavelength of red light is more than that of green light. Code:

Result
Your answer: —  Â·  Correct: D
Explanation

The reason (R) is true: red light has a longer wavelength than green light — red visible wavelengths lie roughly in the 635–700 nm range while green is shorter [2]. The assertion (A) is false because photon energy is proportional to frequency and frequency is inversely proportional to wavelength; thus energy is inversely proportional to wavelength [1]. Therefore, a longer-wavelength photon (red) carries less energy than a shorter-wavelength photon (green). R correctly states a wavelength fact but does not support the incorrect energy claim in A; hence A is false while R is true.

Sources

  1. [2] https://www.nesdis.noaa.gov/s3/2022-02/JPSS%20Understanding%20Infrared%20Light_Teacher-Parent%20Activity%20Manual_Final.pdf
  2. [1] https://www.sciencedirect.com/topics/neuroscience/electromagnetic-radiation
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