Got two questions for ya from my Physics HW, please answer both for high rating!

Question

Got two questions for ya from my Physics HW, please answer both for high rating!!

Q1:

Q2:

Please do not write in cursive because I cannot read it!

7. It seems hard to justify spending 5$ for a compact fluorescent lightbulb when an ordinary incandescent bulb costs 50 cents. To see if this makes sense, compare a 60 W incandescent bulb lasting 1000 hours to a 15 W compact fluorescent bulb having a life-time of 10,0000 hours Both bulbs produce the same amount of visible light and are interchangeable. If electricity costs 0.10 Cents/kwh what is the total cost-purchase plus energy to obtain 10,000 hours of light from each type of bulb? This is called the life-cycle cost.

Explanation / Answer

7.

For Incandescent light bulb

Energy for 10,000 hours of light

E =60*10,000 =6*105 WH

in KWH

E=(6*105)/1000 =600 KWH

Cost of energy =0.1*600 =60 cents =0.6 dollar

Number of bulbs needed for 10000 hours of light

N=10000/1000 =10 bulbs

total cost =10*0.5+0.6 =$5.6

For flourscent light bulb

E=10,000*15 =150000 WH

In KWH

E=150000/1000 =150 KWH

Cost of energy =0.1*150 =15 cents=0.15 dollar

Total cost =5+0.15=$5.15

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