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MHT CET 2026 (13 May, Shift 2) · Matter Waves: de Broglie Wavelength

Matter Waves: de Broglie Wavelength question from MHT CET 2026 (13 May, Shift 2)

Q17MHT CET 2026 · 13 MAY · SHIFT 2Medium

Matter Waves: de Broglie Wavelength

The energy of a photon is equal to the kinetic energy of a proton. If λ1\lambda_1 is the de-Broglie wavelength of a proton, λ2\lambda_2 is the wavelength associated with the photon and if the energy of the photon is EE then (λ1/λ2)(\lambda_1/\lambda_2) is proportional to

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Answer: (b)

  1. Proton: λ1=h2mE\lambda_1 = \dfrac{h}{\sqrt{2mE}}. Photon: λ2=hcE\lambda_2 = \dfrac{hc}{E}.
  2. λ1λ2=Ec2mE=Ec2m\dfrac{\lambda_1}{\lambda_2} = \dfrac{E}{c\sqrt{2mE}} = \dfrac{\sqrt{E}}{c\sqrt{2m}}
  3. So λ1/λ2∝E\lambda_1/\lambda_2 \propto \sqrt{E}: the answer is (b).
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