Electromagnetic waves Flashcards
Are electromagenetic waves longitudinal or transverse waves?
Transverse
Explain why EM waves are not mechanical waves
They can travel through a vacuum
Don’t need a substance to travel through
What do EM waves transfer from their source to an absorber?
Energy
List the different types of waves in EM spectrum in order of DECREASING wavelength (increasing freq)
Radio Microwaves Infrared Visible Ultraviolet X-rays Gamma
What part of the EM spectrum can humans see?
Visible light
How can electromagnetic waves be produced?
Changes inside an atom/atomic nucleus
How are gamma rays produced?
Changes in the nucleus of an atom
E.g. during radioactive decay
How can radio waves be produced?
Oscillations in an electrical circuit
How can we detect radio waves?
Waves are absorbed and create an AC current with the same frequency as the radio wave
What are radio waves used for?
Transmitting television
Mobile phones
Bluetooth signals
What are microwaves used for?
Cooking food
Satellite communications
What is infrared radiation used for?
Heating
Remote controls
Cooking food
Infrared cameras
Which types of EM waves are harmful to the human body?
X-rays
Gamma rays
Ultraviolet
What are the hazards of being exposed to ultraviolet radiation?
Damage to skin cells Sunburn Blindness Age skin prematurely Increased risk of skin cancer
Why are x-rays used for medical imaging?
Pass through flesh, but not bone
