Topic 1- Waves :) Flashcards
Describe a transverse wave and give 2 examples
A transverse wave vibrates perpendicular (at a right angle) to the direction of the energy)
Examples- light waves (all EM waves), water waves
Describe a longitudinal wave ans give an example
A longitudinal wave vibrates parallel to the direction of energy. The only example of this is a sound wave
Frequency
- Known as the number of waves to pass a point in one second
- Measured in Hz, symbol f
- Equations= f = N ÷ T
= T = 1 ÷ f
= V = f × wavelength
Amplitude
- Known as the height of a wave from the centre to the peak or tje trough
- Measured in M, symbol of A
Wavelength (lambda)
- Known as the distance between two similar points on a wave
- Measured in M, symbol of lambda (ƴ upside down)
- Equations= V = f × wavelength
= Wavelength =D ÷ T
Period, T
- Known as the time for ome wave to pass a point
- Measured in S, symbol of T
- Equations= T = 1 ÷ f
Wavespeed
- Known as the distance travelled by one wave in a second
- Measured in ms‐¹, symbol V
- Equations= V = D÷ T
V = f × wavelength
Define a wave
A wave transfers energy by vibrations
Define diffraction
Diffraction is the bending of a wave as it moves past/around an object
Define Refraction
Refraction is the bending of light as it moves from one material to another due to a change in speed
Define the relationship between diffraction and wavelengths
The longer the wavelength, the more diffraction
The shorter the wavelength, the less diffraction
Diffraction causes the shape of a wave to change, but the frequency and wavelength stay the same
High frequency, shorter wavelengths diffraction less
Lower frequency, longer wavelengths diffract more
Name all of the waves included within the EM spectrum
Radio/TV waves -> Microwaves ->
Infrared waves -> Ultraviolet waves -> X-rays -> Gamma rays
Define the relationship between frequency, wavelength and the EM spectrum
The higher the wavelength, the lower the frequency and energy.
Radio/ TV waves have the longest wavelength
Gamma rays have the largest frequency and energy rate
State the speed in which all EM waves travel at
3×10‐⁸ ms-¹
State the EM wave which has the highest frequency
Gamma rays
State the EM wave which has the highest wavelength
Tv/radio waves
State what happens to the frequency and energy as the wavelength increases
They decrease
State what happens to the wavelength as the frequency and energy increase
It decreases
Name a detector for each type or radiation-
Tv/radio- aerial
Microwaves- aerial
Infrared- photodiode
Visible light- photographic film
Ultraviolet- photographic film
X-rays- photographic film
Gamma rays- photographic film
State a non- medical use for each of these EM waves-
Tv/radio- communication
Microwaves- cooking/ communication
Infrared- Night vision equipment
Visible light- light bulbs/ stars
Ultraviolet- scanning bank notes
X- rays- Airport security
Gamma rays- sterilisation of fruit and vegetables
State the definition of refraction
“The change in direction of light as it moves from ome substance to another due to a change in speed”
What is the incident ray?
The ray of light which enters a material
What is the ange of light which enters a material called and whay is its symbol?
The incident angel, written as i
What is the refracted ray?
The ray of light which is refracted as it leaves a material
What is the angle of light which is refracted as it leaves a material and what is it’s symbol?
The refracted angle, written as r
Define “the normal”
The normal is a dashed line drawn at right angles to the material.
It represents 0°
It is where all angles are measured from using a protractor
In what direction does the light go when there is an increase in speed?
Away from the normal
In what direction does the light go when there is a decrease in speed?
Towards the normal
Describe the relationship between frequency and refraction
The frequency always stays the same/ constant
Describe what happens when light goes from a less dense medium to a more dense medium
Speed decreases, wavelength decreases and the angle of refraction is less than the angle of incidence
Describe what happens when light goes from a more dense medium to a less dense medium
Speed increases, wavelength increases, and the angle of refraction is greater than the angle of incidence
