P6 - Waves Flashcards
Waves
Waves transfer energy without the net movement of matter
What is amplitude?
What is wavelength?
Amplitude is the maximum displacement of a point on a wave from its undisturbed
Wavelength is the distance from one point on a wave to the same point on the next wave
What is frequency?
What is period?
What is the equation for period?
Frequency is the number of waves passing a point each second
Period is the time taken (in seconds) for one whole wave to pass a point
Period = 1 / Frequency
What is a transverse wave?
What are examples of transverse waves?
In a transverse wave the vibrations/oscillations are perpendicular to the direction of energy transfer
All electromagnetic waves
Water waves
What is a longitudinal wave?
What are examples of longitudinal waves?
In a transverse wave the vibrations/oscillations are parallel to the direction of energy transfer
Sound waves
Equation for wave speed
Wave speed = frequency x wavelength
What is the electromagnetic spectrum?
longest wavelength & lowest frequency
↓ Radio wave
↓ Microwave
↓ Infrared
↓ Visible light
↓ Ultraviolet
↓ X-ray
↓ Gamma ray
shortest wavelength & highest frequency
Electromagnetic spectrum: Radio wave
What are its uses?
What are the dangers?
Communication (radios, tv)
No known danger
Radio waves in electrical circuits
Radio waves are produced by oscillations (changes in current & potential difference) in electrical circuits
A metal rod can be used as an aerial to receive the signal
The radio waves are absorbed causing an alternating current with the same frequency as the wave
Electromagnetic spectrum: Microwave
What are its uses?
What are the dangers?
Heating food
Communication (satellites, wifi, phones)
Possible heat damage to internal organs
Electromagnetic spectrum: Infrared
What are its uses?
What are the dangers?
Remote controls
Electrical heaters
Motion sensor
Infrared cameras
Short range communication
Skin burns
Electromagnetic spectrum: Visible light
What are its uses?
What are the dangers?
Seeing & taking pictures
Fibre optic
Communication
Bright light causes eye damage
Electromagnetic spectrum: Ultraviolet
What are its uses?
What are the dangers?
Getting a sun tan
Fluorescent bulbs
Eye damage
Sun burn & skin cancer
Electromagnetic spectrum: X-ray
What are its uses?
What are the dangers?
X-rays are absorbed by bones & pass through skin & muscle
X-ray images (medical, airport security)
Kills cells mutations cancer
Electromagnetic spectrum: Gamma ray
What are its uses?
What are the dangers?
Treating cancer
Sterilising medical equipment
Kills cells mutations
Mutations
Cancer
Infrared required practical
What is the best emitter of radiation?
What is the best absorber of radiation?
Emit = lets heat pass through
Absorb = takes heat in
Best emitter of radiation
Best absorber of radiation
↓ Matt black
↓ White
↓ Silver
Worst emitter of radiation
Worst absorber of radiation
