Karteikarten
phys -2
Karten in diesem Stapel (28)
- 1what do waves transfer ?energy
- 2Describe the relationship between oscillation and direction of energy transfer in longitudinal and transverse wavesIn a transverse wave the oscillations are perpendicular to the direction of energy transfer. In longitudinal waves the oscillations are parallel to the direction of energy transfer
- 3What do electromagnetic waves have in common ?They all travel at the same speed in a vacuum
- 4list the parts of the electromagnetic spectrum from longest wavelength to shortestradio
microwave
infrared
visible
ultraviolet
x ray
gamma - 5how does energy and frequency and wavelength change as you go from radio to gamma raysfrequency increases
wavelength decreases
energy increases - 6are electromagnetic waves, sound waves and mechanical waves longitudinal or transverseelectromagnetic = transverse
sound = longitudinal
mechanical = can be either - 7what is the range of wavelengths for electromagnetic waves10-15 meters to 104 meters
- 8draw a diagram to illustrate a longitudinal wave in terms of compressions and rare factions
- 9when does significant diffraction occur ?when the wavelength of the wave is the same as the gap or obstical
- 10when are waves not diffractedwhen the pass along the normal
- 11what is the frequency of a wavethe number of waves generated per second
- 12what is the amplitude of a wavethe height of a wave
- 13what is the wavelength of a wavethe distance from peak to peak of the wave
- 14describe how radio waves , infrared , visible light can be used for communicationradio waves - tv , radio
microwaves - mobile phones satellite tv
infr red - remote controls
vis light - photography - 15draw a ray diagram of a flower in a plane mirror
- 16what determines pitch of a sound and what determines its loudnessthe pitch of a sound is determined by its frequency and loudness by its amplitude
- 17what is the Doppler effectif a wave source is moving relative to an observer there will be a change in the observed wavelength and frequency. the waves source could be light, sound or microwaves. when the source moves away from the observer the observed wavelength increases and the frequency decreases.
- 18what is red shiftthere is an observed increase in the wavelength of light from most distant galaxies. the further away the galaxies are, the faster they are moving , and the bigger the observed increase in wavelength.
- 19how does red shift provide evidence that the universe is expanding and support the big bang theoryred shift shows galaxies are moving away from each other / earth
more distant galaxies show bigger red-shift
more distant galaxies are moving away faster
suggests single point of origin of universe - 20what does a frequency of 440 Hz mean440 waves produced in one second
- 21what is a virtual imageimage cannot be formed on a screen
- 22—
- 23what information can scientists find out about a galaxy when they measure the red shift the galaxy producesdistance from the earth
speed they are moving - 24what properties do radio and microwaves have in commontravel at same speed in vacuum
transfer energy - 25what are the properties of microwaves that allow them to be used for satellite communicationscan pass through ionosphere
- 26in hilly areas it may be possible to receive radio signals but not receive terrestrial tv signal - why ?for waves to diffract around hills
the wavelength need to be similar to the obstacle / gap
tv doesn't have a long enough wavelength to diffract well - 27why was the discovery of CMBR so important to the scientists believing the big bang theory was correctcan only be explained by the big bang
existence predicted by big bang theory
provides further evidence for the big bang - 28how is the wave length of CMBR likely to change in futureincrease
as universe continues to accelerate outwards (expand)
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- 28 Nov 2016
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