A source emits 31.4 W of radiant flux distributed uniformly in all directions. The luminous efficiency is 60 lumen watt⁻¹. What is the luminous intensity of the source?

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Solution

Given that,
Radiant flux = 31.4 W
Since the radiant flux is distributed uniformly in all directions, the solid angle will be 4 $π$
Luminous efficiency = 60 lumen/W
So, luminous flux = luminous efficiency $\times$ radiant flux
= 60 × 31.4 lumen

Luminous intensity = $\frac{Luminous Flux}{Solid angle} = \frac{Luminous Flux}{4 π}$
$= \frac{60 \times (31.4)}{4 π}$
$= 150 candela$

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A source emits 31.4 W of radiant flux distributed uniformly in all directions. The luminous efficiency is 60 lumen watt−1. What is the luminous intensity of the source?

A source emits 31.4 W of radiant flux distributed uniformly in all directions. The luminous efficiency is 60 lumen watt⁻¹. What is the luminous intensity of the source?