AIIMS2007Physics-Optics
AIIMS 2007 Physics Illumination MCQ Question
Type: MCQ-conceptual-Medium-Class 12
A point source is kept at a distance of 1000 m has an illumination I. To change the illumination to 1/6I the new distance should become
A
250 m
B
500 m
C
750 m
D
800 m
Correct Answer
Option A
Detailed Explanation
For a point source, illuminance at a distance r is given by luminous flux x φ / 4πr²
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