Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 12

# A Light Source Emits Monochromatic Light Of 555 Nwavelengthm. the Source Consumes 100 W of Electric Power and Emits 35 W of Radiant Flux. Calculate the Overall Luminous Efficiency. - Physics

Sum

A light source emits monochromatic light of  555 nwavelengthm. The source consumes 100 W of electric power and emits 35 W of radiant flux. Calculate the overall luminous efficiency.

#### Solution

Given:
Wavelength of light, λ = 555 nm

Radiant flux emitted = 35 W

Power input = 100 W

Overall luminous efficiency = "Total luminous flux"/"Power input"=(35xx685)/100=239.75 "lm/W"

So, the overall luminous efficiency will be 240 lm/W.

Concept: Light Process and Photometry
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#### APPEARS IN

HC Verma Class 11, Class 12 Concepts of Physics Vol. 1
Chapter 22 Photometry
Exercise | Q 7 | Page 455
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