DATE:
NAME:
CLASS:
TOPIC 7
PROBLEM SOLVING
BLM 4-20
Applied Power Problems
Goal • Extend your knowledge and understanding of electricity.
What to Do
Write answers to the following questions in the spaces provided.
Questions
1. If a 60 W light bulb in a bedside lamp is only 20 percent efficient in converting electrical energy into light
energy, how many joules of light energy does this light bulb produce each time?
Calculations:
2. (a) How much energy will a 100 W light bulb convert to light and heat if it is left burning for 1 h?
Calculations:
(b) If the bulb is 15 percent efficient at converting electricity into light, how much energy has been lost as heat?
Calculations:
Copyright © 2002 McGraw-Hill Ryerson Limited
DATE:
NAME:
CLASS:
TOPIC 7
PROBLEM SOLVING
BLM 4-20
Applied Power Problems (continued)
3. A 1.5A current passes through a new colour television set when its is connected to a 110 V outlet.
(a) How much power will the TV set use?
Calculations:
(b) If the TV is operating an average of 6 h every day for a week, how many kilowatt hours (kW•h) of
energy will it use in one week?
Calculations:
(c) How many kilowatt hours of energy will the television use in January?
Calculations:
(d) How much energy will the television use in one year?
Calculations:
(e) If electricity costs 12 cents per kilowatt hour, what is the cost of operating this television set for one year?
Calculations:
Copyright © 2002 McGraw-Hill Ryerson Limited