1) When the momentum of a photon is changed by an amount p' then the corresponding change in the de-Broglie wavelength is found to be 0.20%. Then the original moment of the photon was A) 300 p' B) 500 p' C) 400 p' D) 100 p' Answer: Option BExplanation:As, we know de-Broglic wavelength λ=hp ∴ λ∝1p ⇒△pp=−△λλ∴|△pp|=|△λλ| ⇒p′p=0.20100=1500 or, p=500 p'