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

Dear Student,

◆ Answer -

Relative luminosity at the wavelength emitted = 66 %

● Explanation -

Required info : Luminous flux of 555 nm source of 1 W power = 685 lumen

Relative luminosity at the wavelength emitted is -

Relative luminosity = luminous flux of given source / luminous flux of 555 nm source of same power

Relative luminosity = 450 / 685

Relative luminosity = 66 %

Hence, relative luminosity at the wavelength emitted is 66 %.

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Answer 2

The relative luminosity at the wavelength emitted is about 66%

Explanation:

Given data in the question  

The provided source's luminous flux is 450 lumen /watt.

We know the 555 nm source luminous flux of 1 W = 685 lumens

Therefore  Relative luminosity is imparted by,

The simple measure of emitted electromagnetic power (light), the radiant power transmitted by a light-emitting object.

$Relative luminosity =\frac{\text { Luminous flux of the source of given wavelength }}{\text { Luminous flux of } 555 \text { nm source of same power }}$

                               $=\frac{450}{685}$

                                $=0.656 \times 100=65.6 \% \approx 66 \%$

                               $=66 \%$

The relative luminosity at the emitted wavelength is 66%.