Answer :
Total intensity of the 8 Cd and the 12 Cd light source is (8+12) =20 Cd.
Let 
be the distance of the 80 Cd source.
∴ Illuminance due to the 20 Cd source 
is:
------------- (1)
∴ Illuminance due to the 80 Cd source 
is:
--------------- (2)
As
Rate this question :
How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
view all courses
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
RELATED QUESTIONS :
Two light sources
HC Verma - Concepts of Physics Part 1