3.
In 1831, Michael Faraday conducted the first experiments about electromagnetism.
Later he invented the first transformer.
The figures below show the input and output voltage waveforms obtained on the screen
of a cathode ray oscilloscope for Transformer X.
p.d. / V
p.d. / V
240
60
0
0
t / s
t / s
0.02
0.02
Input voltage
Output voltage
a.
Complete the statements below:
i.
Transformer X is a step-down transformer because the output peak voltage is
1
_______________ than the input peak voltage.
ii.
1
What kind of electrical supply is a 9 V battery? _______________.
iii.
What kind of electrical supply is the input and output voltage of any
transformer?
1
_______________.
b.
Using waveforms shown above obtained for Transformer X:
i.
Calculate the frequency of the input voltage.
2
ii.
What is the value of the frequency of the output voltage?
1
__________
c.
Referring to the above waveforms, calculate the number of turns of the secondary coil
of Transformer X given that its primary coil has 2000 turns and assuming 100%
2
efficiency.
Page 4 of 11
Physics – Junior Lyceum – Form 5 – 2011