P1 - Radiation and waves Flashcards
What moves with waves
energy but not particles
What is the amplitude
Gap between centre line and highest point on wave
What is a wavelength
Distance between two crests
What is 1 Hz
1 wave per second
What is the frequencey
Number of wavelengths pass per second
What is the period of the wave
The number of seconds for a wavelength to pass
What direction are the disturbances in transverse waves
90 degrees to the direction
What type of waves are electromagnetic
Transverse
What direction is the disturbances in longitudinal waves
In the direction of the movement
What are some examples of longitudinal waves
Sound waves
Equation for wave speed
Wave speed (m/s) = frequency (Hz) x Wavelength (m)
What to oscilloscopes show
The waveform of a wave
What 3 things can happen when a wave hits a boundary
The wave can be absorbed
Transmitted
or Reflected
What always stays the same in a wave, even if it passes into another medium
the frequency
What is refraction
When a wave hits a different medium, eg. glass, at and angle, and changes direction
What is the order of the electromagnetic spectrum
Radio waves
Microwaves
Infrared waves
Visible light
Ultra violet
X rays
Gamma rays
What happens when high energy waves such as UV, X-rays and Gamma rays
They can ionise the atom
What happens if an electron absorbs an EM wave
It can be excited to a higher radiation level, moving to a higher, partially filled or empty shell
If a high energy wave hits an electron what can happen to it
it can fully leave the atom, ionising it
How do microwaves heat food
They are absorbed into the food, transferring to heat energy
What are some greenhouse gases
CO2, CH4, H2O
What frequency is ultrasound waves
20,000 Hz or above
How does ultrasound imaging work on babies
When the ultrasound leaves the fluid in the womb and enters the babies body, some of it is partially reflected, which can be measured and recorded
What waves to earthquakes produce
Seismic waves
Why do seismic waves change direction in the earth
Because different layers of the earth have different densities, so the waves refract and change directions
Which waves can penetrate all the way through the earth
P waves
Why cant S waves travel all the way through the earth
Because they cannot travel through liquids
What type of waves are P waves
Longitudinal waves
Which wave do we feel first in an earthquake
The P wave
What type of waves are S waves
transverse waves
What is the displacement of the wave
The total distance from peak to trough (2 x amplitude)
If the wave graph is a displacement time graph, what is the distance from peak to peak
The time period of the wave
What is the formula linking frequency and period
Frequency = 1/period
In a denser medium, will transverse waves travel faster or slower
Slower
What is the incident ray
The ray coming in
What is the point of incidence
The point where the incident ray hits the medium change
What is the refracted ray
The ray which has been refracted
What is the emergent ray
The ray which comes out the other side
What is the angle of incidence
The angle from the incident ray to the normal
What is the angle of refraction
The angle from the normal to the ray of refraction
If a wave enters a denser medium, which way will it bend
Towards the normal
If a wave enters a less dense medium, which was will it bend
Away from the normal
What refracts more, blue or red
blue bends best
What in the ear causes hearing loss if damage
cochlea and auditory nerve
