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Electric Power

A light sourc...

Question

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.

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Solution

Given:
Wavelength of light, $λ$ = 555 nm
Radiant flux emitted = 35 W
Power input = 100 W
Overall luminous efficiency = $\frac{Total luminous flux}{Power input} = \frac{35 \times 685}{100} = 239.75 lm / W$
So, the overall luminous efficiency will be 240 lm/W.

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