Unformatted text preview: Fluorescent bulbs are filled with a mixture of argon krypton gas and a small amount of mercury What are the units of measuring light? Correct D ) Lumens Light is measured in lumens The kitchen in your house measures 5 ft by 10 ft. You need to have 50 footcandles of illumination in the room. How many 40 watt bulbs will be required if one bulb emits 500 lumens. (1 footcandle = 1 lumen/sq.ft) Correct C ) 5 bulbs Area of the room = 5 x 10 = 50 sq.ft Lumens required = 50 x 50 = 2500 lumens # of bulbs required = 2500/500 = 5 bulbs CFL bulbs operate at _____ temperatures compared to halogen bulb. Correct A ) Much lower CFL bulbs operate at much lower temperatures compared to halogen bulb. A 16 watt compact fluorescent lamp (CFL) produces 1112 lumens of light. What is the efficacy of the CFL (in lumens/watt)? Correct B ) 69.5 lumens/watt Efficacy = 1112/16 = 69.5 lumens/watt Which one of the following light bulb produces lowest lumens per watt? Correct B ) Incandescent Incandescent light bulb has the lowest lumens per watt A foot candle (fc) is defined as _____. Correct A ) a lumen of light distributed over 1 square foot area A foot candle (fc) is defined as a lumen of light distributed over 1 square foot area Typically, compact fluorescent lamps are how many times more efficient than incandescent lamps? Correct C ) 3 4 times more efficient A 80 watt incandescent light bulb is operated for 15 hours, and a 15 watt fluorescent light bulb is operated for the same period of time. At 10 cents per kWh, what is the cost savings in using the fluorescent bulb? Correct C ) 0.1 Incandescent light bulb Energy consumed = 80/1000 x 15 = 1.2 kWh Energy Cost = 1.2 x 10/100 = $0.12 Fluorescent light bulb Energy consumed = 15/1000 x 15 = 0.225 kWh Energy Cost = 0.225 x 10/100 = $0.0225 Savings in Energy Cost = 0.12 0.0225 = $0.0975 Experts divide lighting uses into three categories. TRUE Energy factor for dish washer is expressed as Number of washes per kWh...
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This note was uploaded on 09/24/2013 for the course EGEE 102 taught by Professor Pisupati,sarmave during the Spring '07 term at Penn State.
 Spring '07
 PISUPATI,SARMAVE

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