Light and Sound Flashcards
What is light?
Light is a transfer of energy from one store of energy to another.
Does light ever curve?
No, it always travels in straight lines.
When will light stop travelling?
When it hits a non-transparent object.
What to do when drawing ray diagrams
Use a ruler and use arrows to indicate directions.
What happens when light hits a transparent surface?
The light hits it and passes through (it gets transmitted).
What happens when light hits an opaque surface?
The light hits it and stops (it gets absorbed).
What happens when light hits a reflective surface?
The lights hits it and bounces off (it gets reflected/scattered).
What do luminous objects do?
They give off light.
How do we see luminous objects?
When the light it emits enters our eye.
Why does light from the sun travel in all directions?
The sun is a sphere.
What is the angle of reflection equal to?
The angle of incidence.
What is refraction?
The change in direction of a wave when it changes speed, typically when moving from one medium to another.
What happens to a light wave if it slows down?
It bends towards the normal.
What happens to a light wave if it speeds up?
It bends away from the normal.
What is the slowest matter that light travels through?
A solid.
What is the fastest matter that light travels through?
A gas.
What matter does light travel through that is slower than a gas but faster than a solid?
A liquid.
What colours can our eyes detect?
Red, green and blue.
What do you get if you mix red and green light?
Yellow light.
What do you get if you mix red and blue light?
Magenta light.
What do you get if you mix blue and green light?
Cyan light.
If you mix 2 colours of light, will it get brighter or darker?
Always brighter.
What colours are you able to see in white light?
All of them.
What is sound caused by?
Something vibrating?
Can sound travel through a vacuum?
No.
Does light travel faster than sound?
Yes.
Why does sound travel?
It makes nearby particles vibrate.
Longitudinal waves
When particles vibrate in the same direction as the wave travels.
Compression
Increase in pressure and density of the air particles around it.
Rarefraction
Decrease in pressure and density of the air particles around it.
Frequency
The number of waves per second.
The highest point in a sound wave
The peak.
The lowest point in a sound wave
The trough.
Amplitude
Half the full wave height
Where the waves stop
Rest position/ Equilibrium
The larger the amplitude…
The louder the sound.
The greater the frequency…
The higher the pitch.
What does sound travel fastest through?
A solid.
What does sound travel slowest through?
A gas.
What matter does sound travel through that is slower than a solid but faster than a gas?
A liquid.
