Flashcards
Physics topic 4 waves (triple)
Flashcards do conjunto (25)
- 1What is a wave?A wave is Something that will carry energy from one place to another. There are different types of waves, some of which require a medium to travel through. Light does not require a medium to travel through.
- 2What is the amplitude?The distance between the middle and top of peak/bottom of trough-volume. (Volume for sound and intensity for light)
- 3What is the wavelength?The distance of length of one whole wave (Pitch of a sound wave and colour of a light wave).
- 4What is the frequency?Number of waves that pass a point in one second (unit=hertz Hz)
- 5What is a Period?The time taken for one wave to pass a point.
- 6What are transverse waves?They are waves in which the vibrations are at right angles to the direction of travel. E.g. Light waves, electromagnetic waves, some seismic waves and and Secondary (s) waves.
- 7What are longitudinal waves?Waves in which the particles move parallel to the direction the wave is travelling in. E.g. Sound waves and Primary (p) waves.
- 8What are some differences between longitudinal and transverse waves?1) Transverse waves have peaks and troughs whereas longitudinal waves have compressions and rarefactions.
2) A transverse wave is measured from peak to peak or trough to trough whereas longitudinal waves are measured from the distance between compressions or rarefactions.
3) In mechanical waves, longitudinal waves can travel through solids, liquids and gases but transverse waves can only travel through solids. - 9How do you measure the velocity of the wavelength using distance and time?Velocity=distance/time
V=X/t
m/s=m / s - 10How is velocity measured when you are given the frequency and the wavelength?Velocity=frequency x wavelength
v=f x λ
m/s = Hz x m - 11How can you measure the speed of a wave (method)?You can measure the speed of a water wave by measuring the time it takes for a wave to travel between two fixed points. For example, you could use a stopwatch and measure the distance between two objects in the water (distance between buoys or ladders). When the wave has passed the point you can then figure out the speed by using the equation velocity=distance/time.
- 12What are the potential outcomes of a wave travelling from one medium to another?1) Bouncing off (reflection)
2) Transmittance (going all the way through)
3) Absorption.
If the wave passes through a new medium it will be refracted at the boundary where it will change speed. - 13What happens to sound waves in the ear?An ear has an eardrum connected to three small bones. Vibrations make the eardrum vibrate and are passed to three small bones (ossicles). it then passes through the semicircular canals until it reaches the cochlea. This turns vibrations into electrical signals which are sent to the brain. The brain interprets the signals as sounds of different pitches and volume, depending on the frequency and intensity.
- 14What is refraction?When a wave passes into a different medium at an angle, it will change speed which causes a change in direction. Light will slow down when passed through a denser medium. Sound will speed up when passed through a denser medium.
- 15What are the rules of refraction?1) Light will bend towards the normal when it passes through a denser medium due to decrease in speed.
2)Light will bend away from the normal when it passes into a less dense medium due to the increase in speed.
3)If the light is shone down the normal, it doesn't change direction. - 16What is the normal?An imaginary line perpendicular to the medium boundary at the point the wave hits the boundary.
- 17What is ultrasound?Sound waves with a frequency too high for humans to hear (higher than 20,000 Hz)
- 18What is a use for ultrasound on a boat?Ultrasound is used in boats to detect if there are any animals underneath them or to measure the distance between the boat and the sea bed. It sends pulses and the speed and time can be measured to work out the distance.
- 19What else is ultrasound useful for?Ultrasound is useful for scanning pregnant women to see if there are any problems and to check for a heart beat. The waves are sent to the womb and then the machine reaches the reflected waves which shows the baby.
- 20What is infrasound?Sound waves that have a frequency too low for humans to hear (under 20 Hz).
- 21Why is infrasound useful?Scientists are able to track animals that use infrasound down for conservation purposes. Also, they can detect natural disasters.
- 22What is the epicentre?The location where the shift in plates occurred producing seismic waves.
- 23What are primary waves?The faster seismic waves that are longitudinal and make buildings vibrate up and down.
- 24What are secondary waves?The slower seismic waves that are transverse and make buildings shake from side to side.
- 25What are 4 differences between p waves and s waves?1) P waves are longitudinal, S waves are transverse.
2) P waves are faster than S waves.
3) p waves can travel through all three states of matter but S waves can only travel through solids.
4) P waves do little damage but S waves do lots of damage.
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- Physics FlashCards sobre Physics topic 4 waves (triple), criado por Jessica Diamond em 07-05-2017.
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- Jessica Diamond
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