Concept explainers
A 850-W toaster, a 1200-W waffle iron, and a 1000-W coffeemaker are all connected to the same 115-V household circuit, fused at 20 A. (See figure 13.19 for a similar arrangement.)
a. What is the current drawn by each of these appliances?
b. If these appliances are all turned on at the same time, will there be a problem? Explain.
c. What is the resistance of the heating element in the waffle iron?
(a)
The equivalent resistance of the two parallel segments.
Answer to Problem 5SP
The current drawn by the toaster is
Explanation of Solution
Given info: The wattage of the toaster is
Different instruments in parallel will draw current depending on the resistance or wattage of them.
Write the formula for the current drawn by the toaster.
Here,
Substitute
Write the formula for the current drawn by the waffle iron.
Here,
Substitute
Write the formula for the current drawn by the coffee maker.
Here,
Substitute
Conclusion:
The current drawn by the toaster is
(b)
When all these appliances are on together whether there will be any problem.
Answer to Problem 5SP
When all appliances are on the circuit will get fused.
Explanation of Solution
Given info: The wattage of the toaster is
The maximum total current that can flow in the circuit is the current at which the circuit will get fuse.
Write the formula for the total current when all the appliances are on.
Here,
Substitute
The total current in the circuit when all appliances are on is
Conclusion:
When all appliances are on the circuit will get fused.
(c)
The resistance of the heating element of the waffle iron.
Answer to Problem 5SP
The resistance of the heating element of the waffle iron is
Explanation of Solution
Given info: The wattage of the toaster is
Write the formula for the resistance.
Here,
Substitute
Conclusion:
The resistance of the heating element of the waffle iron is
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Chapter 13 Solutions
Physics of Everyday Phenomena
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