P12(Wave Properties) Flashcards
What is a wave
-waves transfer energy/information without transferring matter
What are mechanical waves
-vibrations that travel through a medium
What are examples of mechanical waves
-sound waves
-water waves
-waves on springs and ropes
-seismic waves
What are electromagnetic waves
-Waves which can travel through a vacuum at the speed of light
-no medium is needed
-EM waves slow down in a medium
What are examples of electromagnetic waves
-light waves
-radio waves
-microwaves
What are transverse waves
Waves oscillate perpendicular to the direction of energy transfer of the waves
What waves are transverse
-electromagnetic waves
-mechanical waves
What are longitudinal waves
Waves oscillate parallel to the direction of energy transfer of the waves
What waves are longitudinal
-Sound waves
-mechanical waves
What is amplitude
Maximum displacement from rest position
What is wavelength
The distance from a point on the wave to the equivalent point on the adjacent wave
What is frequency
The number of waves passing a fixed point every second
What are units of amplitude, wavelength and frequency
-amplitude and wavelength measured in metres
-frequency measured in hertz
What is the formula for time period
What’s the formula for wave speed
What is reflection
Bending of light without changing a medium
What is refraction
Bending of light with change of medium
When does refraction occur
At a boundary between two different materials because the speed and wavelength of the waves change at the boundary
At a boundary between two different materials waves can be ….
Transmitted or absorbed
What are sound waves
Vibrations that travel through a medium
Sound waves cannot travel …
Through a vacuum(space)
To investigate waves you use a …
-a ripple tank for water waves
-a stretched string for waves in a solid
-a signal generator and a loudspeaker for sound waves
The pitch of a note increases if the ….
frequency of the sound waves increases
The loudness of a note increases if the …
Amplitude of the sound wave increases
Sound waves cause the …
Ear drum to vibrate and the vibrations send signals to the brain
What are ultrasound waves
Ultrasound waves are sound waves of frequency above 20KHz
Ultrasound waves are …
Partly reflected at a boundary between two different types of body tissue
Ultrasound waves reflected at boundaries are …
Timed and the timings are used to calculate distances
An ultrasound scan is …
-Non Ionising
-so it is safer than an x-ray
What’s the formula to calculate the distance travelled by the ultrasound wave
What’s the formula for the depth of the boundary below the surface
What are seismic waves
Waves that travel through the earth
How are seismic waves produced
In earthquakes
What are primary seismic waves(P waves)
-Cause the initial tremors lasting about one minute
-they are longitudinal waves
-they push or pull on material as they move through the earth
What are secondary seismic waves(S waves)
-cause more tremors a few minutes later
-they are transverse waves that travel more slowly than P waves
-they shake the material that they pass through inside the earth from side to side
What are L waves
-cause violent movements on the surface up and down and backwards and forwards
-they travel more slowly than P waves and S waves
-they only happen in the earths crust
What is blackbody radiation
An object that absorbs all of the radiation incident on it and does not reflect or transmit any radiation
