This quiz/test covers work done in an electrical system for an Applied Physics class. The equations for work done in an electrical system are W=V x Q and W=V x I x t.
Please answer click on the correct answer for True/False and Multiple Choice. For short answer questions, answer all questions with complete sentences. For questions involving calculations, show all of your work and circle your answers. If you have technical questions during the quiz, please ask.
Electrical work happens when a voltage doesn’t move a charge.
______ In devices such as rotating motors, radios, and coffee pots, we can’t actually see the electrical work being done. We can only see the results of electrical work.
The unit that describes the amount of coulombs per second traveling through a conductor is the volt.
An electrical motor does 800 N·m of useful mechanical work while it uses up 1000 joules of electrical energy. The efficiency of this motor is ______.
The unit of electrical work is the ______________.
Why do we produce electricity to do work when the process is only 60% efficient?
In electrical systems 1 joule of work is also equal to ________________.
a. b. c. d.
A more efficient motor is one that works ___________________________.
Name an electrical sytem and explay why it is important for a technician to understand how work is done in that electrical system. Be specific with your answer and do not state answers such as, “so the system will work...so the thing doesn’t break.”
If an electric device could operate with an efficiency of more than 100%, would that be an advantage? Explain why or why not.
Explain how you would determine the efficiency of work in an electrical system. What do you need and how do you use it?
From the video, what is the description of electricity?
What prime mover is voltage compared to in this video?
What are the three basic principles of electricity?
How do we find power done by electricity?
You are watching a TV that uses 120V and produces a current of 1.9A. You are home watching the TV for 6 hours of the day, how many watt-hours are produced by the TV? (Hint: take the power of the object divided by the time)
For the following questions, you will need to show all of your work. You can type this in the box or you can write it in the box by using your finger as a pen. Use the formula bank to help calculate your answers.
If a current of 1 amp flows for 60 seconds, how much charge has moved by?
Equation: Work / Answer:
A 220V electric motor draws a current of 40 amperes for five seconds.
How many coulombs of charge are moved?
Equation: Work / Answer:
A 450-N crate is lifted 12 m by an electric motor. The motor is operated on a 120-V outlet from which it draws 3.5 A of current.
a) If the motor is 65% efficient, what is the electrical work done in the system?
Equation: Work / Answer:
Refer to problem 19:
b) What length of time will be needed for it to lift the crate to the desired height?
