Chapter 13 - Electromagnetic Waves Flashcards
Order the electromagnetic waves from the smallest wavelength to the longest wavelength
Gamma rays, X-rays, Ultra Violet rays, Visible light, Infrared, Microwaves, Radio waves
Order the electromagnetic waves from the smallest frequency to the longest frequency
Radio waves, microwaves, infrared waves, visible light, ultra violet rays, x-rays and gamma rays
What speed do electromagnetic waves travel at?
3.0x10^8m/s (300million m/s)
Wave speed equation
Wave speed (m/s) = frequency (Hz) x wavelength (m)
What is visible light
All the light you can see
What is white light
All the colours of the visible spectrum are on it
Radio waves uses
Broadcasting communications carrying TV signals, navigation and radar, studying the universe and astronomy.
Are there any dangers of radio waves
NO DANGERS
Microwaves uses
Mobile phones, satellite transmissions and cooking
Dangers of microwaves
Heats up a liquid, water molecules vibrate when heated, mobile phone can raise your temperature.
Infrared radiation uses
Thermal imaging, television remite controls, short range communication.
Infrared radiation dangers
Heat up your skin causing skin burns
Visible light uses
Vision, photography, illumination
Visible light dangers
Bad for your eyes and potentially damage it
Ultra violet uses
Sun tan beds,security markers for cash, fluroscent lamps
Ultra violet damages
Damage skin from the sun, you can get sunburned and it may cause skin cancer.
X-rays uses
Medical x-rays, airport security cameras
Gamma rays uses
Sterilising equipment, detect cancer and treat it, radioactive tracers
Dangers of gamma rays and x-rays
These rays can pass through substances and knock electrons out of atoms in the substance. This is called ionisation.
How are do carrier waves work?
- An oscillator supplies carrier waves to the transmitter in the form of an alternating current.
- Audio signal is supplied to the transmitter where it’s ued to modulate the carrier waves.
- The modulated carrier waves from the transmitter are supplied to the transmitter aerial.
- When the radio waves are absorbed by a receiver aeriel, they induce an alternating current in the receiver aerial, which causes osciallations on the reciever.
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