Consider a helium He atom that absorbs a photon of wavelength 330   nm . The change in the velocity (in…

Consider a helium He atom that absorbs a photon of wavelength 330 nm. The change in the velocity (in cm s-1) of He atom after the photon absorption is ______ .
(Assume: Momentum is conserved when photon is absorbed.
Use: Planck constant =6.6×10-34 J s, Avogadro number =6×1023 mol-1, Molar mass of He=4 g mol-1)

Solution

P=hλ

mv=hλ

v=hmλ

v=6.6×10−34×6×10234×10−3×330×10−9

v=3×10−1 m/s

v=30 cm/s

∆v = vf-vi=v-0=v = 30 cm/s

Asked in: JEE Advanced 2021 (Paper 2)

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