A fluorescent light source consumes 40 W electric power

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A fluorescent light source consumes 40 W electric power and has a luminous efficacy of 40 lm/W. Illumination in lux at a distance of 3 m from this light source is ______________

1. 175 to 180
2. 165 to 170
3. 75 to 80
4. All of the above

Correct Option: A

To find out Illumination produced from light source.

E =	I
	d²

Where, E = Illumination on surface (lux),
I = Illumination intensity from source (cd)
d = distance from light source
Here, I = Luminous efficacy of lamp × Power consumption of lamp

=	40 lm	× 40 W = 1600 lm
	W

E =	1600	= 177.78 lux
	3²