The inspection department in a factory is currently illuminated by eight overhead incan- descent lamps with reflectors. Each lamp is 100 watts and has a luminous efficacy of 16 lumens/watt. It is proposed that the incandescent lighting be replaced with three fluorescent lamps rated at 40 watts. The luminous efficacy of each fluorescent lamp is 85 lumens/watt. Compare (a) the illuminance levels and (b) annual electricity costs of the two alternatives, given that they will operate three shifts (24 hr/day), 250 days/year, and power cost is 6.5 cents per kW-hr. (c) Each incandescent lamp has a lamp life of 1500 hr and costs $0.60. Each fluorescent lamp has a lamp life of 15,000 hr and costs $6.00. Determine the annual cost of lamps for the two alternatives.