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Here is the "Electrician's Mate 3 - Navy Training Courses"
(NAVPERS 10548) in its entirety (or will be eventually). 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;
1949
CHAPTER 3 QUIZ
ELECTROMAGNETISM AND MAGNETIC CIRCUITS
NOTICE: This page has not been proofed yet!
1. How did Oersted discover that a magnetic field exists around a wire carrying an electric current?
2.
What is the shape or pattern of a magnetic field around a wire carrying an electric current?
3. If you
reverse the current in a wire how does that change the field around the wire?
4. Complete the following
statements: The left hand rule for the field around a conductor says: When the thumb points in the direction of
_________ the fingers point in the direction of _________.
5. How does the field around a conductor
carrying current change with distance from the conductor?
6. Complete the following statements:
(a) When two parallel conductors have currents flowing in opposite directions, their magnetic fluxes
_________ in the space between them.
(b) When two parallel conductors have currents flowing in opposite
directions, their magnetic fields produce a force of _________.
(c) When two parallel conductors carry
currents in the same direction their magnetic fluxes in the space between them _________.
(d) When two
parallel conductors carry currents flowing in the same directions, their magnetic fields produce a force of
_________ between the conductors.
7. Into what shape would you bend a current-carrying wire so that it
would produce the same kind of a field as a bar magnet?
8. A current-carrying coil shaped to produce a magnetic field like the field of a bar magnet is called a
_________.
9. At what place about such a coil is the field strongest?
10. Complete the following statements: When a coil carrying current is grasped in 'the left hand, so the thumb
points in the direction of the _________, the fingers point in the direction of the _________.
11. Complete
the following statements:
(a) If an iron core is placed near a current-carrying coil, the field of
the coil will produce magnetic _________ in the core.
(b) If an iron core is placed near a
current-carrying coil the core will be _________ by the coil.
12. Name three applications, in electrical
gear, for the principle of a current-carrying coil acting on an iron core.
13. Complete these statements:
(a) The current-carrying coil and iron core combination is called an _________-_________-_________.
(b) The closed-loop path followed by magnetic lines is called a magnetic _________.
14. Complete the
following statements:
(a) The greater the magnetomotive force, the greater the _________ in a magnetic
circuit.
(b) The greater the current in the coil of an electromagnet, the the magnetomotive force.
(c) The greater the number at turns in the coil of an electromagnet, the _________ the magnetomotive force.
(d) To increase the magnetic pull of a current carrying coil you
(1) _________ the number of
turns.
(2) _________ the current.
(e) The number of turns of wire in a coil times the
number of amperes flowing in it is called the _________ of the coil.
(f) The unit of magnetomotive force
is called the .
15. Opposition to the flow of magnetic flux in a magnetic circuit is called _________.
16. The ratio of the ability of a material to conduct magnetic flux compared to air as a flux conductor is called
the material's _________.
17. Complete the following statements: Flux produced in a magnetic circuit is
(a) _________ proportional to the magnetomotive force.
(b) _________ proportional to the
reluctance.
(c) Ohm's law for a magnetic circuit can be expressed by the equation Flux= _
18.
Complete the following statements:
(a) The flux density at which an increase in magnetomotive force
will not produce much increase in flux is called the _________ density.
(b) Ability of a material to
retain magnetic flux after the magnetic force is removed is called .
(c) Energy loss due to friction
between molecules when forced into alignment by a magnetic force is called _________.
(d) This energy
loss produces _________ in the magnetic material.
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CHAPTER 3 ANSWERS
ELECTROMAGNETISM AND MAGNETIC CIRCUITS
1. Stay tuned
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