Qstnid -Iv-14-figure Shows A Small Diffused Plane Source S Placed Over A Horizontal Table-top At A Distance Of 2.4 M With Its Plane Parallel To The Table-top. The Illuminance At The Point A Directly Below The Source Is 25 Lux. Find The Illuminance At A Point B Of The Table At A Distance Of 1.8 M From A. <Span Style="background-color: #Ffff00;">figure</span></span> - 22: Photometry - Neet-xii-physics

Home Learn Fast select Course

Show Unit/Chapter Change Unit Change Subject Last Menu

NEET-XII-Physics

22: Photometry

with Solutions - page 3

Qstn# iv-14 Prvs-Qstn Next-Qstn

#14
Figure shows a small diffused plane source S placed over a horizontal table-top at a distance of 2.4 m with its plane parallel to the table-top. The illuminance at the point A directly below the source is 25 lux. Find the illuminance at a point B of the table at a distance of 1.8 m from A.
Figure
Ans : Let x be the distance moved.
Let the illuminance of the candle and the lamp at a distance 1 m be I_C and I_L respectively. According to question,

Page No 455: