Light bulb

Choosingalightbulb1.docx

Name: __________________________ Section: ____ Date: ________________

LAB ACTIVITY: Chapter 20 – Sustainable Energy

Choosing a Light Bulb: The following table provides information on two types of light bulbs available at a local store.

Type of bulb	Estimated lifetime (hours)	Cost per bulb ($)
75 W incandescent	750	0.50
18 W compact fluorescent	7,500	5.00

Assume that

(i) each bulb lasts exactly its estimated lifetime.

(ii) each bulb provides the same amount of usable light.

(iii) the cost of electricity is $0.10 per kilowatt-hour.

(a) Calculate the total lifetime cost for using each type of bulb.

(b) Calculate the total cost of using the incandescent bulb and of using the compact fluorescent bulb for 7500 hours (the lifetime of the compact fluorescent bulb).

(c) Most electricity in the United States is generated by fossil fuel–burning power plants that produce atmospheric pollution. Given that knowledge, explain which type of light bulb has the smaller ecological footprint.