2017 · Q14
Infrared, visible and ultraviolet radiations/ light have different properties. Which one of the following statements related to these radiations/light is not correct?
General KnowledgePhysics
- AThe wavelength of infrared is more than that of ultraviolet radiation.
- BThe wavelength of ultraviolet is smaller than that of visible light.
- CThe photon energy of visible light is more than that of infrared light.
- DThe photon energy of ultraviolet is lesser than that of visible light.
Explanation
Ultraviolet radiation has a shorter wavelength than visible light, and since photon energy E = hc/λ rises as wavelength falls, UV photons are more energetic than visible-light photons — making statement (d) the incorrect one. Infrared has the longest wavelength of the three (statement a is true), ultraviolet the shortest (statement b is true), and visible-light photons indeed carry more energy than infrared photons (statement c is true). Only statement (d) is not correct.