P6: Waves Flashcards
What is the wavelength?
peak to peak or trough to trough
What is the amplitude?
Middle to peak/trough
What is the direction of movement/oscillation for a transverse wave?
Up and down
What is the direction of energy transfer for a wave?
Sideways
What are the different areas of a longitudinal wave called?
- Area of compression
- Area of rarefaction
What is the direction of energy for a longitudinal wave?
Sideways
What is frequency?
The number of waves that pass a point per second
What is the frequency of a short wavelength wave?
High
What is the frequency of a long wavelength wave?
Low
How do we measure time period(s)?
1/frequency(Hz)
What apparatus do we use to measure speed of a wave?
- A ripple tank
- Thing goes in and out producing waves
- Measure wavelength using photo
- Work out frequency
- FREQUENCY X WAVELENGTH
What equation do we use to work out the speed of a wave(m/s)?
Frequency(Hz) x wavelength(m)
What is the angle of reflection equal to?
The angle of incidence i=r
What is the normal line?
A dashed line drawn at 90 degrees to the mirror
What is produced when a sound wave is reflected?
An echo
What type of wave is a sound wave?
A longitudinal wave
What does a sound wave do?
Vibrate the air particles
Eardrum picks up vibration of air particles and turns into sound that your brain can interpret
What is the range of human hearing?
20Hz-20kHz
What can echo/ultrasound be used to do?
Determine distance
Speed = distance / time
Speed is known, measure time taken and calculate distance
There and back, so time is DOUBLE what it would be
What are P waves?
- Primary waves
- Longitudinal
- Travel through solids and liquids
What are S waves?
- Secondary waves
- Transverse
- Only go through solids
What is the order of the electromagnetic spectrum from largest wavelength to shortest wavelength?
- Radiowaves
- Microwaves
- Infrared
- Visible light
- Ultraviolet
- X-Ray
- Gamma Rays
What happens to the energy as the wavelength gets shorter?
Higher energy
What can radiowaves be used for?
Radio communications
What can microwaves be used for?
- Mobile phones
- Heating food
What can infrared be used for?
- Light on remote control
- Heating
What can visible light be used for?
- Cameras
- Seeing
What can ultraviolet light be used for?
- Detecting fake money
- Tanning beds
What can X-rays be used for?
Seeing inside the body e.g. broken bones
What can gamma rays be used for?
- Treating cancers
- Sterilising bacteria
When does diffraction happen?
When a wave passes through a gap
Will curve around when passes through gap
When does refraction happen?
When a wave passes through one medium into another e.g. air into glass
What happens during refraction?
Wave changes direction as the wave changes speed going into another medium
Wave changes speed at different points
What are good absorbers?
- Dark surfaces
- Matt surfaces
What are good emitters?
- Dark surfaces
- Matt surfaces
What are good reflectors?
- Shiny surfaces
What is a converging lens?
- Corrects long sightedness
- Real image
- Magnified
What is a diverging lens?
- Corrects short sightedness
- Virtual image
- Upright
- Small
How is magnification worked out?
Image height / object height
What is the wavelength of red light?
7x10^-7m
What is the wavelength of violet light?
4x10^-7m
What is the frequency of red light?
4x10^14Hz
What is the frequency of indigo light?
7x10^14Hz
What is a black body?
An object in space that perfectly absorbs radiation
