A photon of X-ray has energy of 1 keV. A photon of visible radiation has energy of 3 eV. In this context, which one of the following statements is not correct?
[amp_mcq option1=”The wavelength of X-ray photon is less than the wavelength of visible radiation photon.” option2=”Both the photons have different energies.” option3=”The speeds of both the photons in vacuum are different.” option4=”The frequency of X-ray photon is higher than the frequency of visible radiation photon.” correct=”option3″]
This question was previously asked in
UPSC CDS-1 – 2017
– Statement A: Since E = hc/λ, higher energy means shorter wavelength. E(X-ray) > E(Visible), so λ(X-ray) < λ(Visible). This statement is correct. - Statement B: The energies (1000 eV and 3 eV) are clearly different. This statement is correct. - Statement C: The speed of all electromagnetic radiation (including photons of X-rays and visible light) in vacuum is the constant 'c'. Their speeds in vacuum are the same, not different. This statement is incorrect. - Statement D: Since E = hf, higher energy means higher frequency. E(X-ray) > E(Visible), so f(X-ray) > f(Visible). This statement is correct.