P5f - The Nature of Waves Flashcards
What can interference of light result in?
Light and dark patches or bands.
What can interference of sound result in?
Alternate areas of loud and quiet.
What does coherent light consist of?
Coherent light consists of waves with the same frequency, amplitude and phase.
What does the following wave patterns create?
- crest + crest.
- trough + trough.
- crest + trough.
- big crest.
- big trough.
- no wave.
Why should a laser be used in the single slit experiment?
It produces coherent light.
When are waves in wave?
When they both arrive with a crest or both arrive with a trough.
Fill in the blanks.
If the path difference is a whole number, the interference will be _________.
If the path difference involves half a wavelength, the interference will be _________.
- constructive.
- destructive.
What happens in the double slit experiment?
- the waves from the laser are coherent, and diffract when they go through the slits.
- the diffracted waves overlap, causing interference.
- bands of no light can be seen amongst the laser light.
What does interence indicate to scientists?
That light is made up of waves, as they originally thought that it was made up of particles.
What direction do tranverse waves vibrate?
All different directions.
What happens when transverse waves pass through a polaroid?
- only vibrations in one plane can pass through.
- the waves become plane polarised.
Can all electromagnetic waves be polarised? Can sound be polarised?
- yes.
- no, because it is longitudinal.
When light reflects off water, it is plane polarised. How can polaroid sunglasses be designed knowing this?
They can be designed to allow natural light to pass through but not the glare from the water as they do not allow plane polarised light from the surface of the water to pass through.
What proportion of normal light is likely to be cut out by Polaroid sunglasses?
50% becuase it either stops horizontal waves or vertical waves.
What is meant by wave-particle duality?
Light is made up of waves, and aspects such as diffraction, interference and polarisation are explained in terms of waves. However, reflection and refraction can be described in terms of particles or waves. Light also has one other property, which can only be explained in terms of particles. This is wave-particle duality.
