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Question
Calculate the wavelength, frequency and wave number of a light wave whose period is 2.0 × 10-10s.
Solution
Frequency (ν) of light = `1/"Period"`
`= 1/(2.0 xx 10^(-10)s) = 5.0 xx 10^9 "s"^(-1)`
Wavelength (λ) of light = `"c"/"v"`
Where,
c = velocity of light in vacuum = 3×108 m/s
Substituting the value in the given expression of λ:
`lambda = (3xx10^8)/(5.0xx10^9) = 6.0 xx 10^(-2) "m"`
Wave number (`bar "v"`) of light =` 1/lambda = 1/(6.0xx10^(-2)) = 1.66xx 10^(-1) = 16.66 " m"`
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