Questão 1
Questão
The magnetic field created when a current passes through a coil can be reversed by
Questão 2
Questão
What value of EMF would be induced from an alternator with a conductor of 50cm rotating at a velocity of 20m/s within a magnetic flux density of 5 Tesla
Questão 3
Questão
What value of EMF would be induced from an alternator with a conductor of 0.3m rotating at a velocity of 30m/s within a magnetic flux density of 2 Tesla
Questão 4
Questão
For the direction of current shown the north pole is
Questão 5
Questão
Identify from the solenoid the position of the north pole
Questão 6
Questão
What value of EMF would be induced from an alternator with a conductor of 40cm rotating at a velocity of 25m/s within a magnetic flux density of 3 Tesla
Questão 7
Questão
What value of EMF would be induced from an alternator with a conductor of 250mm rotating at a velocity of 20m/s within a magnetic flux density of 4 Tesla
Questão 8
Questão
Which of the following would be the approximate peak value for a supply of 150V rms
Questão 9
Questão
Which of the following would be the approximate rms value for a peak supply of 180 V
Questão 10
Questão
Which of the following would be the frequency for a time period of 50 milli-seconds
Questão 11
Questão
Which of the following would be the frequency for a time period of 10 milli-seconds
Responda
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10 Hz
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200 Hz
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50 Hz
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100 Hz
Questão 12
Questão
Which of the following would be the frequency for a time period of 25 milli-seconds
Questão 13
Questão
which of the following is the time taken for one cycle of a 400Hz supply
Questão 14
Questão
According to the diagram below y represents
Questão 15
Questão
According to the diagram above X represents
Questão 16
Questão
If the frequency of supply is 1.5kHz, the periodic time is
Responda
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0.66ms
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66ms
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660s
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0.00006s
Questão 17
Questão
If a 0.2m conductor moves at right angles with a velocity of 15m/s though a magnetic flux density of 3T, what is the induced voltage?
Questão 18
Questão
If a 40cm conductor moves at right angles with a velocity of 10m/s though a magnetic flux density of 1.5T, what is the induced voltage?
Questão 19
Questão
If a 60cm conductor moves at right angles with a velocity of 50m/s though a magnetic flux density of 2T, what is the induced voltage?
Questão 20
Questão
If a supply voltage has a value of 240V the r.m.s value is
Questão 21
Questão
Outside a bar magnet the magnetic field goes from
Responda
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South to south
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North to north
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South to north
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North to south
Questão 22
Questão
An AC sine wave has a maximum value:
Responda
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One per cycle
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Twice per cycle
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Three times per cycle
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Never per cycle
Questão 23
Questão
From the diagram below the direction of current is said to be
Responda
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Flowing from A to B
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Flowing from B to A
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Flowing up and down
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In a waveform formation
Questão 24
Questão
To calculate the average value of a sine wave the following multiplier should be used?
Questão 25
Questão
To calculate the root-mean-square r.m.s value of a sine wave the following multiplier should be used?
Questão 26
Questão
What principle would we apply to find the magnetic north pole in this solenoid?
Responda
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Right Hand Grip Rule
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Flemings Right Hand Rule
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Flemings Left Hand Rule
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Lenz Law
Questão 27
Questão
What would be the effect of the two conductors that have the current flowing in the direction shown?
Responda
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The magnetic fields will allow for a resonance to occur and produce sound waves to communicate with other conductors
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The magnetic field would flow and produce a resistance which will oppose the capacitance of an inductor
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The magnetic field would become strong in between the conductors repelling the conductors away
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The magnetic field would strengthen and produce a larger magnetic field around both conductors
Questão 28
Questão
Which of the following is correct?
Responda
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All magnets have five poles
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All magnets have three poles
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All magnets have one pole
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All magnets have two poles
Questão 29
Questão
Which of the following numbers would measure the peak to peak voltage?
Responda
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2 and 3
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1 and 3
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3 and 4
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1 and 2
Questão 30
Questão
Which of the following numbers would measure the periodic time?
Responda
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2 to 4
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1 only
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2 to 3
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1 to 4