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telecoms revision
1.
Here are some statements. Which is true ?
A Sound travels at the same speed as light
B Sound travels faster than the speed of light
C Light travels faster than the speed of sound
A
2.
5.
B
B
C
C
m/s
B
Hz
11.
C
m
D
s
What is wavelength measured in?
A
4.
A
10.
What are the units of frequency?
A
3.
Name:
m/s
B
Hz
C
m
D
s
Sound travels at 330 m/s. How long will it take to travel 990m?
A
0.333s
C
2s
E
4s
B
1s
D
3s
F
5s
Look at the wave. What is the amplitude of the wave and its
wavelength?
12.
13.
7.
8.
9.
A
sound to electrical
D
sound to sound
B
electrical to sound
E
electrical to light
C
sound to light
When transmitting audio signals with AM , it is modulated with a high
frequency wave known as a...?
A
piggyback wave
D
carrier wave
B
traveller wave
E
tidal wave
C
courior wave
Which part of a radio reciever strips the AM (or FM) wave into the
original audio signal?
A
aerial
C
decoder
E
power supply
B
tuner
D
amplifier
F
loudspeaker
At is the speed of radio waves in air?
A
Amp = 1.2m, wavelength = 2m
A
330m/s
D
300,000,000m/s
B
Amp = 2.4m, wavelength =2m
B
1000m/s
E
330mph
C
Amp = 1.2m, wavelength =1m
C
200,000,000m/s
D
Amp = 2.4m, wavelength =1m
14.
6.
What is the energy change that takes place in a microphone?
The law of reflection says that the angle of incidence will be equal to
the angle of reflection. From which two points do we measure the
angle of incidence?
NEED CALCULATOR. What is the wavelength of a radio wave with a
frequency of 300kHz?
A
0.081m
C
810,000m
B
8,100m
D
0.81m
E
810 m
A
from the incident light ray to the normal
B
from the mirror to the incoming light ray
C
from the light beam to the reflected ray
A
red, green and blue
C
red and blue
D
from the reflected ray to the normal
B
red and green
D
blue and green
Light changes speed when going from one medium into another (e.g.
air to glass) If it hits the surface at an angle it will bend. What is this
known as?
A
Reflection
C
Diffraction
B
Refraction
D
Bending of light
15.
16.
45 degrees
D
Critical angle
B
angle of incidence
E
Angle of refraction
C
angle of reflection
Which of these is NOT an advantage of optical fibres over copper
wires?
Diffraction is when waves will bend around objects. What kind of
waves will diffract more?
A
17.
Once the angle of reFRACTion is equal to 90 degrees rays begins to
totally internally reFLECT. What is the name given to this angle which is
different for different sunstances?
A
What colours mix together to give you yellow?
18.
B
short wavelengths
To pick up satellite signals you need a dish (curved refector). What
type?
A
Concave, focus
C
concave, centre
B
convex, focus
D
convex, centre
Geostationary satellites stay above the same point in any part of the
world you want
A
19.
long wavelengths
True
B
False
The period of a satellite can be increased by
A
they carry more information
A
putting it into a lower orbit
B
they are cheaper to make
B
putting it into a higher orbit
C
they travel faster
C
height does not affect the period of a satellite.
D
electrical interference is greatly reduced
20.
assuming that a satellite is directly above you at 36,000km. how long
would it take radio waves to travel from you to it? Need Calcualtor
A
0.12s
B
0.24s
C
2400s
D
1200s
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