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WorksheetsMech 1310 Quiz 3
Total questions: 77
Worksheet time: 3600secs
Opens and shorts in circuits are typical faults
True
False
2. A Thevenin circuit consists of a voltage source with a parallel resistor.
True
False
____ 3. To transfer maximum power to a load, the load resister should be the same as the Thevenin Resistance.
True
False
____ 4. A permanent magnet will retain its magnetism for a long period of time.
True
False
____ 5. Unlike magnetic poles repulse on another.
True
False
____ 6. Magnetic flux in another name for magnetic field.
True
False
____ 7. A conductor with no current through it will still have a magnetic field around it.
True
False
____ 8. Aluminum, brass, and iron make good magnets.
True
False
____ 9. Two north magnetic poles attract one another.
True
False
____ 10. A magnetic field around a conductor is a good indication that current is flowing.
True
False
____ 11. A strong magnetic field around a conductor indicates a small current flowing through the conductor.
True
False
____ 12. The opposition to being magnetized is call permeability.
True
False
____ 13. Soft iron, copper, and silver make good magnets.
True
False
____ 14. Flux lines are concentrated at the center of the magnet.
True
False
____ 15. The left-hand rule can be used to determine the amount of magnetomotive force.
True
False
____ 16. The speed of movement of the coil of a generator affects the direction of current produced.
True
False
____ 17. A solenoid converts electrical energy into mechanical energy.
True
False
____ 18. A DC generator produces a smooth DC voltage output.
True
False
____ 19. The effect on a circuit when an element that draws current from the circuit is connected across the output terminals
Bleeder Current
Load Current
Loading
Balanced Bridge
____ 20. The current left after the total load current is subtracted from the total current into the circuit.
Bleeder Current
Load Current
Loading
Balanced
____ 21. A solenoid consists of ___________.
Two plates separated by an insulator
A burglar alarm relay
A coil of wire wound around a core
A Permanent Magnet
____ 22. In which one of the following applications is electromagnetism used?
Tape Recorders
Loud Speakers
Relays
All of these
____ 23. The polarity of an induced voltage depends on the _____________.
time that the conductor remains stationary in a magnetic field
Length of a conductor in a magnetic field
Direction of motion of a conductor in a magnetic field
Amount of current flowing
____ 24. A relay is a device that ____________.
Uses an electromagnet to open and close contacts
Isolate the actuating signal from the control signal
Has a coil to actuate some contacts that control other circuits
All of these
____ 25. Induced voltage resulting from electromagnetic induction is proportional to:
The rate at which the conductor and magnetic fields move relative to each other
The number of turns of the wire in the coil
The angle at which the conductor cuts the magnetic field
All of these
____ 26. The purpose of a commutator in a dc generator is to:
Maximize the current generated
Provide filtration
Keep current flowing in one direction
Concentrate flux density
____ 27. The voltage produced by a magnetic field cutting through a conductor depends on the ________.
Direction of motion
Speed of motion
Length of the doncutor
All of the above
A certain Thevenin equivalent circuit has a Vth = 6V and an Rth = 75Ω.
Maximum power will be transferred with a load resistor with the value of (a)
29. Two 800Ω are in series and this series combination is in parallel with a 1.4kΩ resister. The voltage across one of the 800Ω resisters is 15V. The voltage across the 1.4kΩ is
(a)
30. Tesla is a unit of (a) .
31. A Wheatstone balanced bridge can be used to measure an unknown (a) .
32. A weber is a unit of (a) .
33. Permeability is the ease of a material to be demagnetized
True/False
True
False
34. A (a) is a type of electromagnet device that has a movable iron core called a plunger.
35. The quantity of lines of force per unit of area is know as (a) .
36. If two north magnetic poles are brought close to each other, a force of attraction pulls them together
True
False
37. The magnetic field around an electromagnet is produced by (a) .
(a)
Find Vout
(a)
A method for analyzing circuits with two or more sources by examining the effects of each source by itself and then combining the effects.
(a)
The output current of a circuit supplied to a load.
(a)
A 4-legged type of bridge circuit with which an unknown resistance can be accurately measured using the balanced state of the bridge. Deviations in resistance can be measured using the unbalanced state
(a)
A force field radiating form the north pole to the south pole of a magnet
(a)
The lines of force between the north and south pole of a permanent magnet or an electromagnet
(a)
The SI unit of magnetic flux, which represents 10^8 lines
(a)
The measure of ease with which a magnetic field can be established in a material
(a)
The opposition to the establishment of a magnetic field in a material
(a)
The cause of a magnetic field, measured in ampere-turns
(a)
An electromagnetically controlled device in which the mechanical movement of a shaft or plunger is activated by a magnetizing current
(a)
A characteristic of a magnetic material whereby a change in magnetism lags the application of the magnetic field intensity
(a)
The ability of a material, once magnetized, to maintain a magnetized state without the presence of a magnetizing current
(a)
Voltage produced as a result of a changing magnetic field
(a)
A law stating that the voltage induced across a coil of wire equals the number of turns in the coil times the rate of change of the magnetic flux/
(a)
A law stating that when the current through a coil changes, the polarity of the induced voltage created by the changing magnetic field is such that it always opposes the change in the current that caused it. The current cannot change instantaneously.
(a)
A
B
C
D
A
B
C
D
A
B
C
D
VA = 5.77V
VB = 6V
Vout = VA − VB = −.226
True
False
Determine Thevenin Equivalent across A and B
Rth =...
(a)
Determine the Thevenin Equivalent across terminals A and B
Vth is...
(a)
Which is the correct Thevenin Circuit
The SI unit of magnetomotive force
(a)
A formation of a group of magnetic lines of force surrounding a conductor created by electrical current in the conductor
(a)
The phenomenon or process by which a voltage is produced in a conductor when there is relative motion between the conductor and a magnetic or electromagnetic field
(a)
The production of a magnetic field by current in a conductor
(a)
A CGS unit of flux density
(a)
A change in current density across a conductor or semiconductor when current in the material is perpendicular to a magnetic field. The change in current density produces a small transverse voltage in the material, called the Hall voltage.
(a)
A characteristic of a magnetic material whereby a change in magnetization lags the application of a magnetic force
(a)
A current induced in a conductor as a result of a changing magnetic field.
(a)
Voltage produced as a result of a changing magnetic field
(a)
Magnetic flux lines that exist in a magnetic field radiating from the north pole to the south pole.
(a)
A force field radiating from the north pole to the south pole of a magnet
(a)
The lines of force between the north and south poles of a permanent magnet or an electromagnet
(a)
The amount of mmf per unit length of magnetic material. The unit is the ampere-turns/meter (At/m); also called magnetizing force.
(a)
An electromagnetically controlled mechanical device in which electrical contacts are open or closed by a magnetizing current.
(a)
An electromagnetic device that converts electrical signals to sound waves.
(a)
In a certain magnetic field the cross-sectional area is 0.4m 2 and the flux is 1400µWb. What is the flux density?
The flux density is...
(a)
