Waves Flashcards
What do waves transfer?
energy
How do waves travel from one place to another?
they oscillate
What is the max height of the wave called?
amplitude
What is the wavelength?
one entire oscillation
What are the 2 ways to work out frequency?
1/time period
wavespeed/wavelength
How do you work out time period?
1/frequency
How do you work out wavespeed?
frequency*wavelength
what greek letter represents wavelength?
Lamda (λ)
What direction are oscillations in transverse and longitudinal?
perpendicular to the direction of energy transfer (T)
parallel to the direction of energy transfer (L)
Example of transverse waves?
EM waves
Examples of longitudinal waves?
sound, seismic waves
What 3 things can happen when a wave hits a surface?
absorption, transmission, reflection
In reflection, which 2 angles are always equal?
angle of incidence = angle of reflection
What is the normal?
a dashed line that is perpendicular to the surface
What is the point of incidence?
the point where the incident ray touches the surface
What is specular reflection?
when the boundary is flat, so the waves reflects in the same direction
What is diffuse reflection?
The boundary is bumpy, so the waves reflect in all different direction (because the normal is at different angles)
What type of image will specular reflection produce?
a clear image
why do waves travel at different speeds through different mediums?
different mediums have different density
What is refraction?
a wave changing direction when passing from one medium into another
Which way will the wave bend when it enter a denser medium?
towards the normal
Which way will the wave bend when it enter a less dense medium?
away from the normal
What is the difference between the frequency and wavelength of a wave when it enters another medium?
if the wave speeds up the wavelength increase and the frequency stays the same (vice versa)
What is the order of the EM spectrum from most ionising to least?
gamma rays, x-rays, uv rays, visible light, infrared, microwaves, radio waves
What 3 things are the same about all EM waves?
they are all transverse
they all travel at 3x10^8 m/s in a vacuum
they all can travel through a vacuum
what is the range of wavelengths for EM waves?
10^4m to 10^-15m
What are the 2 types of lenses?
convex (convergent) and concave (divergent)
What does a convex lens look like and what does it do to light rays?
it has a bulge in the middle and curves to meet at corners at the top and bottom. It causes light rays to refract inwards and converge on a point.