Question
Download Solution PDFThe candle power of a lamp placed normal to a working plane is 60 CP. Find the distance if the illumination is 15 lux.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFConcept:
Illumination is defined as the luminous flux received by the surface per unit area.
It is usually denoted by the symbol ‘E’ and is measured in lux or lumen/m2 or meter candle or foot candle.
Illumination, \(E = \frac{\phi }{A} = \frac{{CP \times \omega }}{A}lux\)
Solid angle \(\omega = \frac{A}{{{d^2}}}\)
Illumination \(E = \frac{{CP}}{{{d^2}}}lux\)
Calculation:
Given that, candle power (CP) = 60 CP
Illumination (E) = 15 lux
⇒ 15 = 60/d2
⇒ d = 2 metres
Last updated on May 29, 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.