Question
Download Solution PDFWhich of the following statements about the law of illumination is correct?
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFLaws of illumination
1.) Inverse square law
This law states that the illumination at any point on a plane is directly proportional to the luminous intensity and inversely proportional to the square of the distance of the surface from the source.
\(E={I\over r^2}\)
But the drawback of inverse square law is that this law is only applicable if the light source is considered as a point source.
2.) Lambert's Cosine Law
The law states that illumination at a point on a plane is proportional to the cosine of the angle of light incident and inversely proportional to the square of the distance of the surface from the source.
\(E={I cos\theta \over r^2}\)
Last updated on Jun 16, 2025
-> SSC JE Electrical 2025 Notification will be released on June 30 for the post of Junior Engineer Electrical/ Electrical & Mechanical.
-> Applicants can fill out the SSC JE application form 2025 for Electrical Engineering from June 30 to July 21.
-> SSC JE EE 2025 paper 1 exam will be conducted from October 27 to 31.
-> Candidates with a degree/diploma in engineering are eligible for this post.
-> The selection process includes Paper I and Paper II online exams, followed by document verification.
-> Prepare for the exam using SSC JE EE Previous Year Papers.