Assume that electricity costs 15 cents per kilowatt- hour. Calculate the monthly cost of operating each of the following:
a 100 W light bulb, 5 h/day
a 600 W refrigerator, 24 h/day
a 12,000 W electric range, 1 h/day
a 1000 W toaster, 10 min/day
Interpretation:
The monthly cost of operating each of the given cases is to be determined.
Concept introduction:
Unit conversion is defined as the process in which multiple steps are used to convert the unit of measurement for the same given quantity. It is determined by multiplication with a conversion factor.
The fraction in which numerator and denominator are the same quantities but are determined in different units, is known as a conversion factor.
Since, 1 kW is equal to 1000 W, hence, conversion factor is as follows:
Answer to Problem 35E
Solution:
Explanation of Solution
a) A 100 W light bulb, 5 h/day
The electricity cost is
Conversion of watt into kilowatt is as follows:
In one month, there are
In one day, the consumption is
The cost of electricity for one kilowatt-hour is
Therefore, the monthly cost is
b)
The electricity cost is
Conversion of watt into kilowatt is as follows:
In one month, there are
In one day, the consumption is
The cost of electricity for one kilowatt-hour is
Therefore, the monthly cost is
c)
The electricity cost is
Conversion of watt into kilowatt is as follows:
In one month, there are
In one day, the consumption is
The cost of electricity for one kilowatt-hour is
Therefore, the monthly cost is
d)
The electricity cost is
Conversion of watt into kilowatt is as follows:
In one month, there are
In one day, the consumption is
The cost of electricity for one kilowatt-hour is
Therefore, the monthly cost is
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Chapter 9 Solutions
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