A good photographic print is obtained by an exposure of 2s at a distance of 1m from a 60 candela lamp. What time of exposure must be given to get equa
A good photographic print is obtained by an exposure of 2s at a distance of 1m from a 60 candela lamp. What time of exposure must be given to get equally satisfactory results at a distance of 2m from a 200 cadela lamp ?
4 views