Question

The luminous flux of a monochromatic source of 1 W is 450 lumen watt⁻¹. Find the relative luminosity at the wavelength emitted.

Answer 1

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 %.