P1.5 The use of waves in communication and evidence for the expanding universe Flashcards
What are the vibrations like in a transverse wave?
The vibrations are at right angles to the direction of travel.
What are the vibrations in a longitudinal wave?
The vibrations are along the same direction as the direction of travel.
Two examples of transverse waves.
Light and water.
Two examples of longitudinal waves.
Sound and P waves (relatively fast moving longitudinal seismic waves that travel through liquids and solids)
What is CMBR (Cosmic microwave background radiation)?
There are microwaves coming from every direction in space.
What can explain the presence of CMBR?
The big bang theory.
What is the amplitude of a wave?
The maximum extent of a vibration or oscillation, measured from the position of equilibrium.
What is the evidence for the BIG BANG?
The light from other galaxies is red-shifted which means the other galaxies are moving away from us.
CMBR
The further away a galaxy is, the more its light is red-shifted and the most likely explanation is that the whole universe is expanding. This supports the theory that the start of the universe could have been from a single explosion.
What is the wave length of a wave?
The wavelength of a wave is the distance between a point on one wave and the same point on the next wave.
What is the frequency of a wave?
The frequency of a wave is the number of waves produced by a source each second.
What does the sun contain?
Helium.
What is the equation to measure wave speed.
Wave Speed = Frequency x Wavelength
v = f x λ
What waves can be used for communicating?
Radio waves, microwaves, visible light and infrared can all be used for communication.
What are radio waves used for?
To transmit television and radio programmes.
What are micro waves used for?
Can be used to transmit signals such as mobile phone calls..
