CBSE 2023 · Region 5 · Set 2 · Q21 · 2 marks
Identify the electromagnetic radiation and write its wavelength range, which is used to kill germs in water purifier. Name the two sources of these radiations.
Marking-scheme solution
Ultraviolet raysWavelength range $\displaystyle 4\times10^{-7}\,\text{m} - 6\times10^{-10}\,\text{m}$Sources :1. The Sun2. Any device in which inner shell electrons in atoms move from one energy level to a lower level.
Electromagnetic WavesElectromagnetic SpectrumRemembervery_short_answereasy
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CBSE Class 12 Physics past-paper question from the 2023board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.