Waves Flashcards
What are progressive waves
Transfers energy without transferring material
What are longitudinal waves
Waves that oscillate parallel to the direction of energy transfer
Transverse waves
Waves that oscillate perpendicular to the direction of energy transfer
Can either longitudinal or transverse waves be polarised
Only transverse waves can be polarised
What are stationary waves
They are formed by the superposition of 2 progressive waves travelling in opposite directions in the same plane with the same frequency, wavelength and amplitude.
What is coherence
A coherent wave has the same frequency and wavelength and a constant phrase difference.
What is Young’s double slit
It is when a coherent source of light is shone through 2 slits of similar size as the wavelength of the light.
Each slit acts as a coherent source therefore a pattern of light and dark fringes are produced.
What does a diffraction grating produce
They produce a much sharper and brighter interference pattern compared to to double slit interference
What is two source interference
Two sources a distance d apart are sending out identical waves in phase
What is monochromatic light
Light with a single wavelength or frequency
What does refractive index mean
Refractive Index is a value calculated from the ratio of the speed of light in a vacuum to that in a second medium of greater density
What does the refractive index measure
The refractive index of a material measures how much it slows down light
What is snells law
The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant, for the light of a given colour and for the given pair of media
n1 sin theta 1 = n2 sin theta 2
What are optical fibres
A very thing flexible tube of glass or plastic fibre that can carry light signals over long distances and around corners.
What are optical fibres used for
High-performance data communication over both short and long distances
