| PHYSICS FORM 4 | |||
1.
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a)
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(i)
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Differentiate between transverse and
longitudinal waves , Giving one
example of each
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(2marks)
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(ii)
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State two characteristic properties of
electromagnetic waves
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(2marks)
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(iii)
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The frequency of an e.m wave is 3.0 x 1014Hz.
Calculate its wavelength and identify the type of e.m wave.
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(2marks)
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b)
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State the properties of the sound from a
vibrating string that will be affected
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(i)
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If the frequency of vibration of the string is
increased.
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(ii)
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If the amplitude of vibration of the string is
decreased.
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(1marks)
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c)
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An earth quake produces transverse waves in the
earth. The graph below shows the ground moves near the Centre of the
earthquake as the waves pass
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Determine the
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(i)
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amplitude
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(1marks)
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(ii)
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Period
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(1marks)
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(iii)
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Frequency of the earthquake
wave
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(1marks)
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(iv)
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If the wavelength of the
wave is 2m, calculate the speed of the wave.
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(1marks)
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RADIOACTIVITY
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2.
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The following readings were observed from a G.M.
counter every 2minutes after it was switched on in a physics laboratory: 20,
25, 23 , 26, 16
A radioactive substance was next introduce in
front of the counter and the following readings were observed after every 10
hours
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(i)
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Define
background radiation
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(1mark)
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(ii)
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Calculate
background radiation
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2marks
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(iii)
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Draw another table for corrected count rate and
time
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1marks
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(iv)
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Plot a graph of corrected count rate against time
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(4marks)
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(v)
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Determine the half-life of the radioactive
substance from your graph
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(2marks)
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ELECTRICITY
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3.
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(a)
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A charge of 2.4 x 10-4C due to
movement of electric charges is carried past a point in an electric circuit
in 2.0 x 10-3s.
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(i)
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Determine the size of the current in the circuit.
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(2
marks)
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(ii)
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Determine the number of electrons that have
passed through the point in this time. (The charge on an
electron, e = 1.6 x I 0-19
C)
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(2
marks)
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(iii)
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If a p.d of 240 V is responsible for this
movement of charges, calculate this work done in moving the electrons in 2 x
10-3 s
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(2
marks)
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(iv)
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Hence, calculate the power involved.
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(2
marks)
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(b)
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Figure 1 shows three resistors connected to a 12
V battery with meters A and V connected in their correct positions
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(i)
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Name the meters
A and V
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(2 marks)
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