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The magnetic field created when a current passes through a coil can be reversed by
adding capacitance
increasing the frequency
reversing the current
increasing the number of turns
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
50 V
500 V
5 V
5000 V
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
1.8 V
1800 V
18 V
180 V
For the direction of current shown the north pole is
above the solenoid
at the left of the solenoid
at the right of the solenoid
below the solenoid
Identify from the solenoid the position of the north pole
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
300 V
33 V
3 V
30 V
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
200 V
22 V
20 V
2 V
Which of the following would be the approximate peak value for a supply of 150V rms
212 V
106 V
235 V
95 V
Which of the following would be the approximate rms value for a peak supply of 180 V
115 V
255 V
127 V
282 V
Which of the following would be the frequency for a time period of 50 milli-seconds
25 Hz
20 Hz
50 Hz
40 Hz
Which of the following would be the frequency for a time period of 10 milli-seconds
10 Hz
200 Hz
100 Hz
Which of the following would be the frequency for a time period of 25 milli-seconds
which of the following is the time taken for one cycle of a 400Hz supply
5 mS
250 mS
2.5 mS
25 mS
According to the diagram below y represents
the peak amplitude
the peak to peak amplitude
the frequency
the time period
According to the diagram above X represents
If the frequency of supply is 1.5kHz, the periodic time is
0.66ms
66ms
660s
0.00006s
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?
11v
1.5v
3v
9v
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?
15v
60v
12v
6v
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?
100v
166v
If a supply voltage has a value of 240V the r.m.s value is
240V
255V
260V
170V
Outside a bar magnet the magnetic field goes from
South to south
North to north
South to north
North to south
An AC sine wave has a maximum value:
One per cycle
Twice per cycle
Three times per cycle
Never per cycle
From the diagram below the direction of current is said to be
Flowing from A to B
Flowing from B to A
Flowing up and down
In a waveform formation
To calculate the average value of a sine wave the following multiplier should be used?
0.543
0.89
0.707
0.637
To calculate the root-mean-square r.m.s value of a sine wave the following multiplier should be used?
0.2
0.88
0.7071
What principle would we apply to find the magnetic north pole in this solenoid?
Right Hand Grip Rule
Flemings Right Hand Rule
Flemings Left Hand Rule
Lenz Law
What would be the effect of the two conductors that have the current flowing in the direction shown?
The magnetic fields will allow for a resonance to occur and produce sound waves to communicate with other conductors
The magnetic field would flow and produce a resistance which will oppose the capacitance of an inductor
The magnetic field would become strong in between the conductors repelling the conductors away
The magnetic field would strengthen and produce a larger magnetic field around both conductors
Which of the following is correct?
All magnets have five poles
All magnets have three poles
All magnets have one pole
All magnets have two poles
Which of the following numbers would measure the peak to peak voltage?
2 and 3
1 and 3
3 and 4
1 and 2
Which of the following numbers would measure the periodic time?
2 to 4
1 only
2 to 3
1 to 4