P1.5 Waves and the expanding universe (2) Flashcards
What is the normal?
A construction line PERPENDICULAR to the reflecting surface at the point of INCIDENCE
What is the angle of incidence equal to?
The angle of reflection
Is the image produced in a plane mirror real?
No, it is virtual
How do sound waves produce sound?
The waves cause VIBRATIONS in a medium, which are detected as sound
What is the pitch of a sound determined by?
What is the volume of a sound determined by?
Frequency
Amplitude
What is an echo?
A reflection of a sound
What is the Doppler effect?
That a wave source is moving RELATIVE TO OBSERVER and there is a CHANGE in the observed WAVELENGTH and FREQUENCY
What could the wave sources be in the Doppler effect? Give three possible options.
Light, sound or microwaves
What happens to the observed frequency and wavelength as the source moves AWAY from the observer
- Wavelength increases
- Frequency decreases
What is the red shift effect? (2)
Inc. in wavelength of light from most distant galaxies.
The FURTHER away, the FASTER they move, the BIGGER the inc. in WAVELENGTH
What is fundamental idea ‘Big Bang’ theory?
That the universe began from a very small initial point
What does CMBR stand for and what is it?
Cosmic microwave background radiation
A form of EM radiation filling the universe
How does the observed red-shift provide evidence that the universe is expanding?
The further from us a star is, the more its light is red-shifted
What is the only theory that supports CMBR?
The ‘Big Bang’ theory
Where does CMBR come from?
Radiation that was present shortly after the beginning of the universe
