Flashcards
Physics AS Level Module 4: Section 2- Waves
Flashcards do conjunto (35)
- 1progressive wavea wave which carries energy from one place to another without transferring any material (the source of the wave loses energy)
- 2ways to tell that waves carry energy*electromagnetic waves cause things to heat up
*x-rays and gamma rays can ionise (knock electrons out of their orbits)
*loud sounds cause vibrations
*wave power can generate electricity - 3displacementhow far a point on the wave has moved from its equilibrium position
- 4amplitudethe maximum magnitude of the displacement of a wave
- 5wavelengththe length of one whole wave cycle e.g. from crest to crest etc.
- 6periodthe time taken for a whole cycle to complete
- 7frequencythe number of cycles per second passing a given point
- 8phasea measurement of the position of a certain point along a wave cycle
- 9phase differencethe horizontal distance by which a wave lags or leads another wave
- 10frequency =1/period (1 Hz = 1s^-1)
- 11wavespeed =frequency x wavelength
- 12how to find the wave frequency using an oscilloscope...find period of the wave using the timebase and the length of a cycle of the wave (count the squares across one cycle and multiply by the timebase) then use f=1/T equation to find frequency
- 13transverse wavesa wave in which particles oscillate at a right angle to the direction of energy transfer e.g. electromagnetic waves
- 14two main ways of drawing transverse waves...displacement against distance and displacement against time (both graphs look the same)
- 15longitudinal wavesparticles oscillate in the same direction as the direction of energy transfer
- 16plotting a longitudinal wave graph...a displacement against time graph will look like the transverse wave graphs
- 17intensitythe rate of flow of energy per unit area at right angles to the wave (W/m^2)
- 18intensity =power/area or power/4πr^2
- 19why is intensity proportional to amplitude squared..?intensity is proportional to energy and energy of a wave depends on the square of the amplitude
- 20properties of electromagnetic waves...*speed in a vacuum is always 3x10^8 m/s
*all are transverse waves consisting of vibrating electric and magnetic fields
*can all be refracted, reflected and diffracted
*all progressive waves which carry energy
*as they are transverse, they can be polarised - 21wavelength of radio waves...10^-1 -- 10^6
- 22wavelength of microwaves...10^-6 -- 10^-3
- 23wavelength of infrared....7 x 10^-7 -- 1 x 10^-3
- 24wavelength of visible light...4 x 10^-7 -- 7 x 10^-7
- 25wavelength of ultraviolet...1 x 10^-8 -- 4 x 10^-7
- 26wavelength of x-rays...1 x 10^-13 -- 1 x 10^-8
- 27wavelength of gamma rays...1 x 10^-16 -- 1 x 10^-10
- 28penetration and uses of radiowaves...can pass through matter and is used for radio transmition
- 29penetration and uses of microwaves...can mostly pass through matter and causes heating and is used for radar, microwave cooking and TV transmissions
- 30penetration and uses of infrared...mostly absorbed by matter, causing it to heat up and is used as a heat detector, night vision cameras, remote controls and optical fibres
- 31penetration and uses of visible light...absorbed by matter causing some heat and is used for human sight and optical fibres
- 32penetration and uses of ultraviolet...absorbed by matter, slightly ionising and is used in sunbeds and security marks that show up under UV
- 33penetration and uses of x-rays...mostly pass through matter whilst causing ionisation and is used to see damaged bones and teeth, airport security and to kill cancer cells
- 34penetration and uses of gamma rays...mostly pass through matter whilst causing ionisation and is used for irradiation of food, sterilisation of medical equipment and to kill cancer cells
- 35—
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- AS level Physics :) FlashCards sobre Physics AS Level Module 4: Section 2- Waves, criado por Rosie Marsh em 26-10-2018.
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- Rosie Marsh
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