Question

A light bulb emitting 1750 Im of luminous flux shines on a book that is 3.0

Answer 1

The illumination of the book is found to be approximately equal to 15 lx.

Option 1.

Explanation:

Luminous flux is the measure of power of the light emitted from a source and illumination is the property of the light to illuminate a given surface when it falls on the surface. So the measure of the region the light flux illuminates the surface is termed as illumination.

As here the luminous flux is given as 1759 lm and the distance of the object which has to be illuminated is placed 3 m away from the source ,the illumination is found to be directly proportional to the luminous flux and inversely proportional to the square of the distance between them

$illumination = \frac{Luminous flux}{4\pi d^{2} } \\\\illumination = \frac{1750}{4*3.14*3*3} = 15.48 lx = 15 lx$

So, the illumination of the book is found to be approximately equal to 15 lx.