Standard Grade Physics
1.
Telecommunications
Ink Exercise G1
A pupil whistles a note into a microphone connected to an oscilloscope and the pattern
observed is shown in the diagram below
Without changing the controls on the oscilloscope, a second pupil whistles a louder note of
lower frequency into the microphone. Which of the following shows the pattern which
would be observed on the screen?
(KU1)
2.
The diagram shows part of an experimental wave tank used to test model oil rigs.
There is a wave generator at one end of the tank. Two depth markers, P and Q, are fixed to
the bottom of the tank.
(a)
(i) Ten waves are made in 5 seconds. Calculate the frequency of the waves.
(KU2)
(ii) The distance from the wave generator to the other end of the tank is 12 metres.
Eight complete waves are made in this distance.
Calculate the wavelength of the waves.
(KU2)
(iii) Calculate the speed of the waves.
(KU2)
(b)
(i) As the waves travel along the tank, the length of depth marker P seen above the water
changes from 15 centimetres to 13 centimetres.
Calculate the amplitude of the waves at depth marker P.
(KU2)
(ii) Why is the amplitude of the waves at depth marker Q smaller than at P?
(PS1)
3. The diagram shows children using a large float in a swimming pool. A wave machine
in the swimming pool generates 24 waves per minute on the surface of the pool.
(a) Show that the frequency of the wave machine is 0.4 hertz.
(PS2)
(b) The wavelength of the waves in the pool is 4.0 metres.
Calculate the speed of the waves in the pool.
(KU2)
(c)The large float moves up and down on the waves. The vertical distance through which the
float rises is 0.5 metres.
What is the amplitude of the waves?
(PS1)
4.
Two different communication systems are used at a concert. One is for public
announcements and the other is used by security staff.
(a) Public announcements are made using a microphone and are heard by the audience from
loudspeakers.
What energy transformation takes place in
(b)
(i)
the microphone
(ii)
the loudspeakers?
(KU2)
Two members of the security staff communicate using two-way radios. Each radio
consists of a transmitter and a receiver.
(i)
At what speed do signals travel between the two-way radios?
(KU1)
(ii)
Explain why no cables are needed to carry the signals between one radio
and the other?
(PS2)
TOTAL 20
Standard Grade Physics
4.
B Decoder
E Loudspeaker
(KU1)
C tuner
D aerial
E decoder
(KU1)
TV signals are sent from Britain to the USA using a satellite link. The device which sends
the signals from Britain is called the
A modulator B decoder
4.
C Amplifier D Battery
The part of a radio which picks up all the signals from the air is called the
A modulator B amplifier
3.
Ink Exercise G2
Which of the following is the source of energy in a portable radio?
A Tuner
2.
Telecommunications
C loudspeaker D amplifier E transmitter
The period of a satellite orbit depends on
A
the mass of the satellite
B
the height of the satellite above the Earth
C
the average length of an Earth day
D
whether the satellite orbits above the equator or is in a polar orbit
E
the rate at which the Earth is spinning
(KU1)
(KU1)
3.
The frequency range and some uses of different radio wavebands are shown.
(a)
Give a use, from the table, for a radio wave which has a frequency of
106 megahertz.
(PS1)
TV is broadcast in the United Kingdom on the UHF waveband.
What is the range of frequencies in this waveband?
(PS1)
(b)
4.
A reporter from the local radio station is present at the opening of a new factory.
The reporter has to get her radio report back to the radio station in time for the next
Bulletin. She telephones in her report.
(a) Give one advantage of using a telephone in everyday life.
(KU1)
(b) A girl, listening to her radio, hears the broadcast of the report of the opening of
the factory. The table below shows the frequency range of the different wavebands
on her radio receiver.
Waveband
long wave
medium wave
high frequency
F.M.
Frequency Range
30 kilohertz – 300 kilohertz
300 kilohertz – 3 megahertz
3 megahertz – 30 megahertz
30 megahertz – 300 megahertz
(i) The radio station she is listening to has a frequency of 570 kilohertz.
State the waveband of this radio station.
(PS1)
(ii) Give a possible frequency of a radio station which transmits in the F.M. waveband.(PS1)
(iii) The main parts of a radio receiver are listed below.
Aerial Tuner
Decoder Amplifier
Loudspeaker
Electricity supply
Which part is used to select a particular radio station?
6.
(KU1)
A caller makes a telephone call using a mobile phone. The call is received at a
telephone in a house.
The message from the caller reaches the person receiving the call in four stages.
Stage 1 – The caller speaks into the mobile phone
Stage 2 – The mobile phone transmits a signal to an aerial at a receiving station
Stage 3 – The signal is transmitted along an optical fibre to an exchange
Stage 4 – The exchange is connected by a wire link to a telephone in the house.
(a)(i) Use the words from the list below to state how the message is transmitted at each of
the above stages.
electrical
light microwave sound
(stages1-3 PS3)
(stage 4 KU1)
(ii)
During which stage (1 – 4) does the message travel most slowly?
(PS1)
(b)
Copy and complete the diagram below to show the effect of the curved reflector at
the receiving station.
(KU2)
(c)
A section of the optical fibre used in Stage 3 is shown below.
Copy and complete the diagram to show how the signal is transmitted along the
optical fibre.
(PS2)
TOTAL 19
Standard Grade Physics
5.
Telecommunications
Ink Exercise C1
At a local swimming gala, the swimmers start when they hear the sound of the starting
horn. This horn also sends an electronic signal to start timing the race.
At the start of the race, the swimmer in lane 1 is a distance of 2m from the horn and the
swimmer in lane 8 is a distance of 19m from the horn.
(a)
(b)
The swimer in lane 1 hears the sound of the horn first. Calculate how much later the
swimmer in lane 8 hears the sound.
(PS3)
As each swimmer finishes the race, an electronic touch sensor detects the swimmer’s arrival
at the finishing point. After the race, the scoreboard gives the following information.
(i)
(ii)
Using your answer to part (a), or otherwise, explain why the swimmer
in lane 8 should be awarded first place.
(PS2)
Suggest an improvement to the starting, or timing, system that would
reduce the unfairness of the timing.
(PS1)
6.
The depth of the seabed is measured using pulses of ultrasound waves. The ultrasound
waves are transmitted from a stationary ship. The waves are reflected from the seabed as
shown and are detected by equipment on the ship. The transmitted ultrasound waves have a
frequency of 30 kHz and travel at a speed of 1500 m/s in water.
(a)
One pulse of ultrasound waves is received back at the ship 0.2s after being sent out.
(b)
(i)
Calculate the depth of the seabed.
(KU3)
(ii)
Calculate the wavelength of the ultrasound waves in the water.
(KU2)
The ultrasound waves lose energy as they travel through the water. The transmitted
wave is displayed on an oscilloscope screen as shown below.
Copy and complete the bottom part of the diagram to show the trace produced by the
reflected wave.
(PS2)
(c)
The frequency of the transmitted wave is increased to 60 kHz.
What happens to the time interval between the transmitted pulse and the
reflected pulse.
(PS2)
TOTAL 15
Standard Grade Physics
Telecommunications
Ink Exercise C2
7.
The tuning dial on a radio displays three different bands which are labelled frequency
modulation (FM), medium wave (MW) and long wave (LW). The frequency range for each
band is shown below.
(a)
The radio receives a signal with a wavelength of 1190m.
To which of the above bands is the radio tuned?
You must show clearly the calculation used to reach your conclusion.
(b)
(KU3)
Signals cannot be received from one of the bands when this radio is used in a village
which lies in a deep valley surrounded by hills.
(i) Explain which band is not received.
(KU2)
(ii) Houses in the village are unable to receive programmes from the local TV station
but can receive satellite TV programmes broadcast on similar frequencies.
Suggest an explanation for this.
(PS2)
2. (a) At a science exhibition, a display has two videophones connected together.
A videophone is a special telephone, which can be used to send both video signals (for
pictures) and audio signals (for sound) along a telephone link.
(i) A video signal used to test the link produces the
black and white pattern shown.
Describe how a black and white pattern is built up on the screen.
(KU2)
(ii) It is only possible to send 3 complete pictures every second along the link to the
receiving videophone.
Explain why a person’s movement as seen on the videophone, appears jerky.
(KU2)
(b)
Another display has been set up to show how different colours can be seen on a TV screen.
Switches R, G and B on a panel control each of the electron guns in the TV. Each switch
turns a gun off when pressed. The colour controlled by each switch is shown in the table
below.
What colour is the screen when the display is on and
(i)
(ii)
(iii)
no switches are pressed;
only switches B and G are pressed;
only switch B is pressed?
(PS3)
3.
In 1996 the Olympic Games were held in the city of Atlanta in the USA.
(a)
TV pictures of the Games were transmitted from the USA to Britain. The TV signals were
carried by microwaves. The microwaves travelled from the USA to Britain via a
geostationary satellite positioned 36 000 km above the surface of the Earth as shown in the
diagram below.
(b)
(i)
What is meant by saying that the satellite is geostationary?
(ii)
The frequency of the microwaves used was 12 GHz.
Calculate the wavelength of the microwaves used in the transmission.
(KU2)
(PS2)
Newspaper reporters at the games were able to fax their reports back to Britain by a
telephone link. The telephone link used an 8000 km length of glass optical fibre.
(Speed of light in glass = 2.0 x 108 m/s)
How long did it take the telephone signals to travel from the USA to Britain?
(PS2)
TOTAL 20