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Description
Flashcards by gfhgfhg gfhgfhg, updated more than 1 year ago
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Created by gfhgfhg gfhgfhg
almost 8 years ago
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| Question | Answer |
| what do waves transfer ? | energy |
| Describe the relationship between oscillation and direction of energy transfer in longitudinal and transverse waves | In 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 |
| What do electromagnetic waves have in common ? | They all travel at the same speed in a vacuum |
| list the parts of the electromagnetic spectrum from longest wavelength to shortest | radio microwave infrared visible ultraviolet x ray gamma |
| how does energy and frequency and wavelength change as you go from radio to gamma rays | frequency increases wavelength decreases energy increases |
| are electromagnetic waves, sound waves and mechanical waves longitudinal or transverse | electromagnetic = transverse sound = longitudinal mechanical = can be either |
| what is the range of wavelengths for electromagnetic waves | 10-15 meters to 104 meters |
| draw a diagram to illustrate a longitudinal wave in terms of compressions and rare factions | |
| when does significant diffraction occur ? | when the wavelength of the wave is the same as the gap or obstical |
| when are waves not diffracted | when the pass along the normal |
| what is the frequency of a wave | the number of waves generated per second |
| what is the amplitude of a wave | the height of a wave |
| what is the wavelength of a wave | the distance from peak to peak of the wave |
| describe how radio waves , infrared , visible light can be used for communication | radio waves - tv , radio microwaves - mobile phones satellite tv infr red - remote controls vis light - photography |
| draw a ray diagram of a flower in a plane mirror | |
| what determines pitch of a sound and what determines its loudness | the pitch of a sound is determined by its frequency and loudness by its amplitude |
| what is the Doppler effect | if 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. |
| what is red shift | there 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. |
| how does red shift provide evidence that the universe is expanding and support the big bang theory | red 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 |
| what does a frequency of 440 Hz mean | 440 waves produced in one second |
| what is a virtual image | image cannot be formed on a screen |
| what information can scientists find out about a galaxy when they measure the red shift the galaxy produces | distance from the earth speed they are moving |
| what properties do radio and microwaves have in common | travel at same speed in vacuum transfer energy |
| what are the properties of microwaves that allow them to be used for satellite communications | can pass through ionosphere |
| in 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 |
| why was the discovery of CMBR so important to the scientists believing the big bang theory was correct | can only be explained by the big bang existence predicted by big bang theory provides further evidence for the big bang |
| how is the wave length of CMBR likely to change in future | increase as universe continues to accelerate outwards (expand) |
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