1. Lamps of 800 cd and 1200 cd are mounted 4mapart on a level surface. A vertical screen is arranged between the lamps so that its surfaces are normal to the lamps. The screen is 2.5mfrom the 800 cd lamp. Calculate the illuminance of both sides of the screen. 2.Two lamps, each of intensity 2400 cd, are mounted 6 m above a level roadway and 20 m apart. Calculate the illuminance of the road surface (a) directly beneath one lamp, (b) halfway between the points beneath the lamps and (c) 4 m from the point beneath one lamp, and between them.
