From the expression
`lamda =c/v`
We get
`v=c/lamda ……..1`
Where,
ν = frequency of yellow light
c = velocity of light in vacuum `3xx 10^(8) m//s` lt brgt `lamda` = wavelength of yellow light = 580 nm = `580 xx 10^(-9) m`
`v=(3xx10^(8))/(580xx10^(-9))=5.17xx10^(14)s^(-1)`
Thus, frequency of yellow light emitted from the sodium lamp
` 5.17 xx10^(14)s^(-1)`
Wave number of yellow light `barv=1/lambda`
`1/(580xx10^(-9))=1.72xx10^(6)m^(-1)`
