Waves Flashcards
What phenomena tells us that light is a particle?
The photoelectric effect
What does shining light through a diffraction grating show us?
That light is wave
What is the formula for finding the wavelength?
Wavelength = planck constant/ mass x veloctiy
What are the conditions for observing diffraction?
Diffraction patterns are only visible if the wavelength of the particle is roughly equal to the width of the diffraction grating.
Electrons are very small so it’s possible to reduce their de broglie wavelength to the distances between atoms in a crystal.
What is frequency?
It’s the no.of oscillations per second
What is the period?
the time taken to complete one oscillation
What is the phase of a wave?
It describes how far through the cycle of the wave is.
What is the phase difference?
It’s a measure of the difference in where two waves are in their cycle.
How can it the phase difference be measured?
In angles or radians
What type of wave can be polarised?
Transverse
What is polarised light?
The light where the electrical field is oscillating in one direction.
What is a polariser?
An optical filter that only allows transverse waves at particular angles to pass through.
What is a stationary wave?
A wave that is formed when two progressive waves, each with the same frequency, wavelength and moving in opposite directions interfere with one another.
What is a node?
It is a point on a stationary wave that has zero amplitude.
What are antinodes?
They’re points on a stationary wave with maximum amplitude
