Physics- waves Flashcards
What type of wave are sound waves? (in air)
Longitudinal
What type of waves are waves in water?
Transverse
What type of waves are Electromagnetic waves?
transerve
What type of waves are p waves?
longitudinal
What type of waves are s waves?
transverse
What is the frequency of a wave?
The number of waves passing a point every second
What is the amplitude of a wave?
the maximum distance of a point on a wave away from its undisturbed position
What is the wavelength of a wave?
the distance from a point on one wave to the equivalent point on the adjacent wave
Can transverse waves travel through liquids?
no
Can longitudinal waves travel through liquids?
yes
What are the properties of P waves?
longitudinal, travels through solids and liquids, fastet
What are the properties of S waves?
transverse, solids only, slower
If a wave slows down in a new medium, how will its direction change?
it will bend towards the normal
If a wave slowls down in a new medium, how will its direction change?
towards the normal
What do lenses do, and what are the two types of lenses?
They use refraction to bend light rays to form an image. There are two types: concave and convex
What do convex lenses do?
Causes light travelling parallel to the axis to converge at the principal focus
What dies the speed in which light travels through a medium depend on?
Optical density
Is a mirror’s image virtual or real?
virtual
What is the difference between diffuse and specular reflection?
Specular -light rays reflecting off a smooth, shiny object. Diffuse- an irregular surface scatters the light (still reflection!)
Would you use the words “diffuse” and “specular” to describe reflection or refraction?
reflection
In which order do earthquake waves arrive?
p waves -> s waves -> surface waves
What is infrasound?
sound with a frequency lower than 20
What is ultrasound?
sound with a frquency higher than 20,000
What is frequency measured in?
Hz (hertz)
How do humans hear sound? (5 steps)
- sound waves collected by outer ear
- waves travel along the auditory canal
- waves reach eardrum, which vibrates
- ossicles, amplify vibrations
- cochlea turns them into electrical signals, which are sent along the auditory nerve to the brain
the different parts of the ear can only vibrate at certain frequencies due to their shape, size and structure
list some uses of ultrasound
sonar
foetal scanning
cleaning
medical treatment/diagnosis
How does echolocation work? (3 steps)
- animal emits ultrasound
- reflects off object
3.animal recieves echo, they calculate distance to prey/object/etc from the time delay (VERY IMPORTANT YOU MENTION THE TIME DELAY)
How do you calculate uncertainty?
1/2 X range
How do you present the final results of an investigation?
mean +/- uncertainty
How do you improve the speed of sound experiment (the playground one, at least)
Increase distance- walk further, use echo
What are mechanical waves?
waves that require a medium to propagate
What can gamma rays be used for?
medical tracing, radiotherapy, sterilisation
how does radiotherapy work?
high doses of radiation kill cells so gamma rays are targeted at cancerous cells taking care to avoid healthy ones. Done by using low amounts of gamma rays in different directions so only the cancerous cells get a lethal dose
how do medical tracers work?
a radioactive gamma emitting isotope is ingested and gamma rays are detected to see where the isotope travelled to
