reflection, refraction and sound Flashcards
when waves reach the boundary of a medium what could happe?
they could reflect,absorb refract,or transmit
what are the mian afctos for constructing a ray diagram?
rays must be drawin wit a ruler
- each ray should have an arrow drawn on them
- when the ray meets boundary a normal should be drawn at right angle to the boundary
-all relevant angles should be labelled
What does refraction depend upon?
The angle at which the wave hits the boundary,and the materials involved
What is the refractive index?
The way in which a material affects refraction
Refraction is due to the_____?
The wave speed in different media
What is an ultrasound wave always greater than?
20 kHz
What happens when an ultrasonic wave meets a boundary between two different medi
It is partially reflected
How do you determine how far a way a boundary is?
Measure the time taken for reflected ultrasonic waves to return to a detector
What is uktr around usually used for?
Medical uses e.g. finding kidney stones,tumours,and foetuses
What is echo sounding used for?
Detecting objects in deep water and measuring the depth of water
In echo sounding what exactly happens?
The wave travels through the water and reflects back after hitting something and the time taken for the wave to come back determines the distance
What is the equation for echo sounding?
Distance=speed X time
What is the “speed” in the echo sounding equation?
1500m/s as this is the general speed of sound in water
What are the two types of seismic waves performed in earthquakes?
P-waves and s-waves. Primary and secondary waves
What are the features of p-waves?
They are longitudinal waves
The travel at the speed of sound and are twice as fast as S-waves
They travel at different speeds through solids and liquids
What are the features of S-waves?
They are transverse waves
They are not able to travel through liquids
when talking about waves What three things happen in an earthquake?
- Seismic waves travel outwards from the earthquake and are capable of travelling all the way through the earth
- seismic waves travel in a curved path through the earth due to the earth’s increasing density with depth
- Protective placed around the earth measure when and where the different waves arrive
What are the two different shadow zones?
S-wave shadow zone and P-wave shadow zone
What are the features of the s wave shadow zones?
S waves are not able to travel through the liquid outer core of the earth
this results in a large shadowzone on the opposite side of the earth to where the earthquake originated
The Shadow zone provides evidence of the size of the earth’s core
P-wave shadow zone features:
P waves are able to travel through the liquid outer core
however they are refracted at the boundary between the semi-solid mantle and the liquid
They are refracted again on the boundary between the liquid outer core and solid inner core
These refractions result in p wave shadow zones
The study of these shadow zones is used to determine the size and composition of the inner and outer core
