Chapter 6, ELECTRICAL ENERGY AND POWER Video Solutions, Electricity 1: Devices, Circuits and Materials

Problem 1

An electric soldering iron takes 5 amperes at 110 volts. What is the power used in watts? In kilowatts? _________________________________________________
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Kayla Gephart

Numerade Educator

00:48

Problem 2

A device is rated at 1,100 watts. What current is required if it is operated at 110 volts? ____________________________________________________________
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Kayla Gephart

Numerade Educator

01:32

Problem 3

A motor must lift an elevator car weighing 2,000 pounds to a height of 1,000 feet in 4 minutes, at a constant speed. What horsepower rating is required of the motor? ___________________________________________________________
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Aja S

Numerade Educator

03:12

Problem 4

Find the cost of operating ten 100-watt lamps, at their rated voltage, for 11 hours at a rate of 10 cents per kilowatt-hour. __________________________________
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Rick Geesaman

Numerade Educator

04:19

Problem 5

Determine the overall efficiency of a motor that delivers 2 hp to a load if it draws 7.5 amperes when connected to a 240-volt supply. ________________________
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Ghazala Khan

Numerade Educator

01:23

Problem 6

An electric toaster has a rating of 1,000 watts at 120 volts. What current will it draw? ____________________________________________________________
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Vidhi Bhatt

Numerade Educator

00:55

Problem 7

The toaster in problem 6 (same heating element) is connected to a 240-volt circuit. What power will it use? ________________________________________

Vishal Gupta

Numerade Educator

02:29

Problem 8

Determine the cost of operating a 2-watt electric clock for 365 days at 3 cents per kilowatt-hour. ______________________________________________________
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Jacob Adamczyk

Numerade Educator

02:46

Problem 9

A transformer primary circuit (input) draws 12 amperes when connected to a 2,400-volt source. An ammeter connected in the secondary circuit (output) indicates 115 amperes at 240 volts. Calculate the percent efficiency of the transformer.
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Mayukh Banik

Numerade Educator

00:53

Problem 10

A 5-ohm heating element draws 20 amperes from the power source. How many kilowatts of power are delivered to this element? __________________________

Manish Kumar

Numerade Educator

02:50

Problem 11

Determine the power that is taken by $R_2$ in Figure 6-3.
FIGURE CANT COPY
Figure 6-3 Finding power.
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Salamat Ali

Numerade Educator

01:08

Problem 12

For the circuit in problem 11, what is the total power of both resistors combined?
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Anurag Kumar

Numerade Educator

Problem 13

Find the power at $R_3$ in Figure 6-4.
FIGURE CANT COPY
Figure 6-4 $\mathrm{R}_1$ Finding power.
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05:08

Problem 14

For the circuit in problem 13, find the total power of the circuit.
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Kajal Gautam

Numerade Educator

02:52

Problem 15

What is the power taken by $R_4$ in the circuit for problem 13 ?
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Vishal Gupta

Numerade Educator