topic 6 - waves

Question 1

describe the difference between longitudinal and transverse waves.

Answer 1

The oscillations of a longitudinal wave is parallel to the waves direction of energy transfer. Whereas the oscillations of a transverse wave is at a right-angle to the waves direction of energy transfer.

Question 2

what equipment is used to measure speed or sound

Answer 2

oscilloscope

Question 3

what equipment is used to measure the speed of water ripples

Answer 3

strobe light

Question 4

define amplitude

Answer 4

maximum displacement of a point on the wave from its understood position

Question 5

state a transverse and longitudinal wave example

Answer 5

transverse: ripples on the surface of the water, electromagnetic waves
longitudinal: sound waves

Question 6

wavelength, wave speed & frequency equation.

Answer 6

wave speed = frequency x wavelength

Question 7

Describe how an electrical signal generates a radio wave in a TV signal transmitter. Explain how this radio wave can generate an electrical signal in a distant TV aerial.

Answer 7

• Alternating currents are made up of oscillating charges/electrons.
• As the electrons oscillate in the transmitter, they produce oscillating electric and radio waves.
• Radio waves are transmitted to and then absorbed by the distant TV aerial.
• This causes the electrons in the receiver to oscillate.
• Which generates an electrical signal.
• This alternating current has the same frequency as the original current.

Question 8

A family from northern England are on holiday in France. They are unable to listen to their local FM radio station from back home. However, they are still able to listen to the same long-wave radio broadcasts as they do at home. Explain why?

Answer 8

• FM radio is transmitted using very short wavelength radio waves.
• These radio waves can only be received if the receiver is in the direct sight of the transmitter.
• Because wavelengths are easily absorbed by obstacles.
• So the signal cannot be received in France.
• Long wave radio waves can be transmitted over long distances.
• Because long-wave radio waves can also diffract around the curved surface of the Earth.
• And also diffract around obstacles eg. mountains.
• Hence the signal can be received in france