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Q14 (CDS-II/2017) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Waves and acoustics Answer Verified

Infrared, visible and ultraviolet radiations/ light have different properties. Which one of the following statements related to these radiations/light is not correct?

Result
Your answer:  ·  Correct: D
Explanation

The electromagnetic spectrum is ordered by increasing frequency and decreasing wavelength as follows: radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays, and gamma rays. Infrared radiation has wavelengths (700 nm to 1 mm) longer than visible light (400–700 nm), while ultraviolet radiation has the shortest wavelengths (10–400 nm) among the three [1]. According to Planck's equation (E = hf or E = hc/λ), photon energy is directly proportional to frequency and inversely proportional to wavelength. Consequently, UV radiation, having the highest frequency and shortest wavelength, possesses the highest photon energy. Visible light has more energy than infrared but less than ultraviolet. Therefore, the statement claiming ultraviolet photon energy is lesser than that of visible light is incorrect.

Sources

  1. [1] https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html
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