P13 - Electromagnetic Waves Flashcards
Why type of waves are electromagnetic waves?
They are ALL transverse waves
Does every electromagnetic wave IN A VACUUM travel at the same speed?
YES
What speed do ALL electromagnetic waves in a VACUUM travel at?
300 million metres per second
What is inversely related in the electromagnetic spectrum?
The wavelength and frequency are inversely related
What does it mean when the wavelength and frequency are inversely related?
When one of them increases, the other decreases
What is the order of all the different waves in the spectrum
Radio waves, microwaves, infared, visible light, ultra violet, x-rays, gamma rays
What is the only electromagnetic wave humans can detect on the electromagnetic wave spectrum?
Visible light
What colours is visible light made up of?
Red
Orange
Yellow
Green
Blue
Indigo
Violet
Why can (ultra violet, x-rays and gamma rays) be dangerous to humans?
They are ionising which can cause damage to our cells
Which two waves are used for communication?
Radio waves
And
Microwaves
What electromagnetic wave has the longest wavelength and lowest frequency?
Radiowaves
What electromagnetic wave has the shortest wavelength and highest frequency?
Gamma rays
Why do we call the electromagnetic wave spectrum, electromagnetic?
Because its made up of oscillating electric and magnetic fields
How do generate radiowaves?
Using electricity in the form of sn alternating current
What are alternating currents made up of?
Oscillating charges
What are three types of radiowaves we use for communication? (Its simple)
Longwaves
Short waves
Very short waves
Why do we use long waves of radiowaves for huge distances?
The can bend around the curved surface of the earth
What are the two types of microwaves?
Waves absorbed by water molecules
and
Waves that arent absorbed by water molecules
What are the micro waves that arent absorbed by water molecules used for?
Satelites for communication as the atmosphere has water
What are the micro waves that ARE absorbed by water molecules used for?
Heat our food as the watermolecules in food are absorbed and vibrate
What are the micro waves that ARE absorbed by water molecules used for?
Heat our food as the watermolecules in food are absorbed and vibrate
Where is infared radiation emitted from?
All objects that have thermal energy
How can visible light also be used for communication?
Using optical fibres (thin glass fibres) that are able to transmit pulses of light over long distances
What is fluorescence?
A property of certain chemicals where ultra violet is absorbed and then visible light is emitted
Where might you see fluorescence?
A painting with chemicals
(A fluorescent painting)
What do X-rays allow us to do?
Help us view the internal structure of objects like bones
What can gamma rays sterilise?
Medical equipment and food
Why are gamma rays so useful for sterilisation?
They can kill microorganisms without causing any other damage
Why dont hospitals just use boiling water to sterilise medical equipment
Equipment made of materials like plastic can get damaged
