Lightning is seen before thunder is heard because

1
Lightning is seen before thunder is heard because

• Sound travels faster than light
• The thunder has a greater distance to travel than
  the lightning
• Light travels faster than sound

2
A sound takes 4 s to travel 1360 m. The speed of
sound is

• 0.029 m s-1
• 5440 m s-1
• 340 m s-1
• 300 000 000 m s-1

3
The frequency of a wave is

• The number of waves passing in 10s
• The time it takes 1 wave to pass a point
• The number of waves passing in 1s
• The time it takes 10 waves to pass a point

4
Wavelength is

• The distance between a crest and trough
• The distance between the middle of a wave and the
  crest
• The distance between successive crests

5
Waves travelling at 10 m /s have a frequency of 4
Hz. Calculate the wavelength

• 40 m
• 2.5 cm
• 0.4 m
• 2.5 m

6
The mouthpiece of a telephone contains

• A loudspeaker that turns ES to EE
• A microphone that turns ES to EE
• A microphone that turns EE to ES
• A loudspeaker that turns EE to ES

7
On a CRO a high frequency , loud sound would be
displayed as

• Small number of waves and big amplitude
• Large number of waves and small amplitude
• Small number of waves and small amplitude
• Large number of waves and big amplitude

8
Fibre Optic cables are

• Hollow cylinders of glass
• Thick pieces of glass like string
• Thin threads of glass

9
Calculate how long it takes light to travel down
a fibre optic cable 20 km long

• 1.0 x 10 4 s
• 1.0 x 10 -4 s
• 4 x 10 12 s

10
Which part of a radio receiver separates the
carrier wave from the transmitted information ?

• Aerial
• Tuner
• Decoder
• Loudspeaker

11
The amplifier

• Increases the frequency of the signal and leaves
  the amplitude unchanged
• Increase the amplitude and the frequency
• Decreases the frequency and amplitude
• Changes the amplitude but leaves the frequency
  unchanged

12
In amplitude modulation

• A low frequency carrier wave is added to a high
  frequency sound wave
• The carrier wave frequency changes with the
  frequency of the sound
• A low frequency sound wave is added to a high
  frequency carrier wave

13
Colour on a TV screen is produced by

• Red, green and blue electrons hitting a screen
• Electrons hitting three different colours of
  phosphor
• Red, blue and green light being fired from an
  electron gun

14
White light is produced by

• Mixing equal intensities of red, green and blue
  light
• Mixing red and blue light
• Mixing green and blue light
• Mixing red and green light

15
Radio and TV waves travel through air at

• 340 m /s
• 3 x 10 8 m/s

16
TV reception is more difficult in hilly areas
than radio because

• Long wavelengths diffract less than short ones
• Short wavelengths diffract more than long ones
• Long wavelengths diffract more than short ones

17
Satellites are needed to broadcast from
Dunfermline to New York because

• Short wavelength TV waves diffract around the
  earth
• Short wavelength TV waves travel in a straight
  line out into space
• Short wavelength TV waves dont transfer enough
  energy

18
Satellite aerials need a curved reflector behind
them to

• Gather the microwave signal over a big area and
  focus it
• Gather the microwave signal over a big area and
  retransmit it
• Look cool
• Weaken the strength of the signal as it is too
  strong for the aerial

19
A geostationary satellite

• Is fixed in position
• Orbits 36 000 km above the orbit and has a period
  of 48 hours
• Orbits 36 000 km above the equator and has a
  period of 24 hours
• Orbits 2 000 km above the equator with a period
  of 12 hours

20
The wavelength of a 9 GHz microwave signal is

• 0.03 m
• 30 m
• 2.7 x 1018 m