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Question
Find the wave number of a photon having energy of 2.072 eV
Given : Charge on electron = 1.6 x 10-19 C,
Velocity of light in air = 3 x 108 m/s,
Planck’s constant = 6.63 x 10-34 J-s.
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Solution
E = hv
`:.v=E/h`
`v=C/lambda`
∴ Wave number
`1/lambda=v/c`
`=E/(hc)`
`=(2.072xx1.6xx10^(-19))/(6.63xx10^(-34)xx3xx10^8`
`=1/lambda=1.667xx10^6m^(-1)`
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