Here is the "Electricity  Basic Navy Training Courses"
(NAVPERS 10622) in its entirety. It should provide one of the Internet's
best resources for people seeking a basic electricity course  complete with examples
worked out. See
copyright. See
Table of
Contents. • U.S. Government Printing Office; 1945  618779
Chapter 7 Quiz  Electrical Power
1. Does an empty lamp socket have force?
2. Is any work done by an open circuit?
3. Is any power consumed by an open circuit?
4. A generator supplies a 72 ampere load at 600 volts. What is the power consumed
by the load in watts? In kilowatts? In hp?
5. A 50 hp motor draws 80 amperes at 600 volts. What is the power input? Power
output in watts? Efficiency?
6. The prime mover of a generator furnishes 37 hp to the generator. The electrical
load on the generator is 70 amperes at 440 volts. What is the power input in watts?
Power output in watts? Efficiency?
7. A power line has a drop of 18 volts in transmitting a load of 75 amperes.
How much power is lost in this line?
8. What is the resistance of the line in problem 7?
9. If a line consumes 650 watts in transmitting 55 amperes, what is the potential
drop?
10. How much power will be consumed by a 75 hp motor operating at 80 percent
efficiency? In hp? In watts? In kilowatts?
Return to Chapter 7
Chapter 7 Answers
Electrical Power
1. Yes. There is an emf present. It tries to force current across the open circuit
but cannot.
2. No, as long as no current flows it is a case of force but no motion.
3. No. Again, force but no motion.
4.* 43,200 w. 43.2 kw.
57.9 hp.
5. 48,000 w. 37,300 w.
77.7 percent.
6. 27,602 w. 30,800 w.
89.6 percent.
7. 1,350 w.
8. 0.24 ohm.
9. 11.8 v.
10. 93.75 hp. 69,937.5
w. 69.94 w.
* The original manual gave this as an incorrect answer: 16,128
w. 16,128 kw. 2.16 hp.
Thanks to Lou Nickles for finding the error.
