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Question
The luminous flux of a monochromatic source of 1 W is 450 lumen watt−1. Find the relative luminosity at the wavelength emitted.
Solution
Given,
The luminous flux of the given source is 450 lumen/watt.
We know that luminous flux of 555nm source of 1 W = 685 lumens
∴ Relative luminosity is given by,
`"Luminous flux of the source of given wavelength"/"Luminous flux of 555nm source of same power"=450/685=66%`
So, the relative luminosity at the wavelength emitted is 66 %.
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