Flashcards
Waves
Cards in this deck (32)
- 1Define displacementThe distance and direction of a particle from the equilibrium position
- 2Define amplitudeThe maximum displacement of a vibrating particle
- 3Define wavelengthThe shortest distance between two particles in phase
- 4Define frequencyNumber of wave cycles occurring per second
- 5Define wave speedDistance travelled by a wave each second
- 6Define phase differenceMeasured in degrees or radians, the amount by which one wave lags behind another wave
- 7Define path differenceMeasured in meters, the difference in length of two waves
- 8Define progressive waveWaves whose oscillations travel and transfer energy
- 9Which type of waves can be polarised?Transverse waves
- 10Uses of polarisationReduce glare in polaroid sunglasses
TV and radio signals are polarised by the direction of the rods on the transmitting aerial. - 11Define superpositionThe point where waves meet
- 12What is the total displacement at a point where interference is occurring?The sum of the individual displacements at the given point
- 13When do waves constructively interfere?When they're in phase with each other
- 14When do waves destructively interfere?When they're in anti-phase with each other (180 out of phase)
- 15When are stationary waves formed?When two progressive waves with equal and opposite velocities, equal wavelengths and similar amplitudes interfere with each other.
- 16What is the name given to frequencies at which stationary waves are formed?Harmonic frequencies
- 17Define diffractionThe spreading out of waves when they pass through a gap or over an edge
- 18When is diffraction most noticeable?When the gap width is the same size as the wavelength
- 19What happens to monochromatic light when it passes through a slit?It will display a diffraction pattern
- 20What happens to white light when it passes through a slit?It displays a spectra of colours
- 21Define coherenceThe waves have the same frequency with a constant phase difference
- 22What happens to light entering a less dense material?It refracts away from the normal
- 23Define the critical angleThe angle of incidence such that the angle of refraction is 90 degrees and the light is refracted along the boundary
- 24What happens if the angle of incidence is greater than the critical angle?It is reflected back inside the medium. This is called total internal reflection.
- 25In optical fibres, what part has a higher refractive index (Or is denser)?The core
- 26In optical fibres, what part has a lower refractive index (Or is less dense)?Cladding
- 27Why does light totally internally reflect in optical fibres?The diameter of the optical fibre is so thin that the angle of incidence is always bigger than the critical angle
- 28What are the two causes of signal degradation in optical fibres?Absorption
Dispersion - 29What causes loss of amplitude in optical fibres?Some of the energy getting absorbed into the material.
- 30What causes pulse broadening in optical fibres?Dispersion of light
- 31What is modal dispersion in optical fibres?Some rays taking longer to get to the receiver based on the path they take
- 32What is material dispersion in optical fibres?Different frequencies travelling at different speeds in the core, which means that they get to the receiver at different times.
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- A level Physics Flashcards on Waves, created by Ben Donovan on 19/09/2019.
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- Ben Donovan
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