P12 - Electromagnetic Waves Flashcards
What are Electromagnetic Waves?
Transverse waves that transfer energy from the source of the waves to an absorber.
What order do the waves come in the Electromagnetic Spectrum?
1) Radio Waves
2) Microwaves
3) Infared Radiation
4) Visible Light
5) Ultraviolet
6) X-rays
7) Gamma Rays
What is colour spectrum on Visible Light?
Red to Violet
What wave has the Longest Wavelength and the Lowest Frequency?
Radio Waves
What wave has the Shortest Wavelength and the Highest Frequency?
Gamma Rays
What has a shorter wavelength Visible Light or Infared Radiation?
Visible Light
What has the Lowest Frequency Ultraviolet or X-rays?
Ultraviolet
What is the only Electromagnetic Wave can our eyes detect?
Visible Light
How are the waves grouped in the Electromagnetic Spectrum?
Wavelength and Frequency
What velocity do electromagnetic waves travel at?
The same velocity through a vacuum (space) or air.
What practical applications are radio waves used for?
Television and Radio
What practical applications are microwaves used for?
Satellite communications and Cooking Food
What practical applications are infared used for?
Infared Cameras and Cooking Food
What practical applications are Visible Light used for?
Fibre Optic Communications
What practical applications are Ultraviolet used for?
Sun Tanning and Energy Efficient Lamps
What practical applications are X-rays used for?
1) Airport Security
2) Medical X-Rays and CT Scan
What practical applications are Gamma Rays used for?
1) Sterilisation of Medical Equipment
2) Cancer Therapy (Radio Therapy).
What is the Wave Speed Equation?
Wave Speed (m/s) = Frequency (Hz) x Wavelength (m)
What are the Dangers of Radio Waves?
No known Dangers
What are the dangers of Microwaves?
Can penertrate the body and heat internal organs.
What are the dangers of Infared Radiation:
It can damage, burn or kill skin cells (heats up cells).
What are the dangers of Visible Light?
Can damage your eyes.
What are the dangers of Ultraviolet?
Sun Burn, can lead to skin cancer and damages eyes.
What are the dangers of X-rays?
- Can cause cancer, as it MUTATES DNA.
- Kills Cells
What are the dangers of Gamma-Rays?
Tissue Damage and Kill Cells
What wave is associated with Heat?
Infared Radiation
A siren emits a note which has a frequency of 430 Hz and a wavelength of 0.8 m. What is the speed of this sound?
Wave Speed = 430 x 0.8
= 344 m/s
What is the wavelength of a sound wave with frequency 100 Hz and Wave Speed of 344 m/s?
Wave Length = Wave Speed / Frequency
Wave Length = 344 / 100
= 3.44 m
What sort of Radiation is X-rays and Gamma Rays and what does that mean?
Ionising radiation, which causes the mutation of genes (DNA) and cancer.
What does Radiation Dose mean?
Is a measure of the risk of harm resulting from an exposure of the body to the radiation.
What Unit is measured for Radiation Dose?
Sievert (1 seivert = 1000 millisieverts)
Where do Gamma Rays originate from?
Changes in the nucleus of an atom.
If one can has a Matte Black outside surface and the other a Shiny Aluminium surface which will gain heat easiest?
The matte black surface will due to fact that black and matte are better absorber unlike the shiny aluminium surface which which reflect the heat.
How can radio waves be produced?
By oscillations in electrical circuits.
How do radio waves travel far distances?
When radio waves are absorbed they may create an alternating current with the same frequency as the radio wave itself, so radio waves can themselves include oscillations in a electric circuit.
What waves are used for Nuclear Weapons?
Gamma Rays
What do changes in the atoms and the nuclei of atoms have on electromagnetic waves?
Being generated or absorbed over a wide frequency range (very destructive).
