Uses of EM waves :wavy_dash: :ocean: (X rays and gamma rays :hospital: (…
Uses of EM waves :wavy_dash: :ocean:
X rays and gamma rays :hospital:
:warning: Ionising radiation (knock electrons out) so can cause cancer and mutations but you can wear a film badge. Gamma rays are shorter wavelengths so can penetrate more.
Short wavelengths at the end of the visible spectrum and can carry much more waves per second than longer wavelengths. X-rays are produced when electrons or particles that move at high speeds stop. Gamma rays are produced when unstable nuclei release energy. X-rays can find cracks in metals and limbs (the more dense an object is, the more it absorbs). Gamma rays kill bacteria on food and surgical instruments. Beam of gamma rays can destroy tumour cells but not neighbouring tissue.
Medical imaging and treatments, killing bacteria on foods
Glow in the dark objects since chemical absorb UV rays and emit visible light.
:warning: can cause blindness, sunburn and skin cancer, also age the skin, because UV waves are smaller than visible light and so carry more energy
Energy efficient lamps, sun tanning
Visible light :sunny:
Light can be focused on a lens. Light waves cant escape the fibre and are reflected back into the fibre. Has a shorter wavelength so can carry much more pulses of waves than radio waves, therefore OF can carry much more information. OF is more secure as signals stay in the fibres.
Fibre optic communications
:warning: absorbed by skin and can damage and burn them due to heat. The hotter an object is, the more IR radiation it emits.
Used in optic fibres because infrared is absorbed less than visible light in glass fibres. Suitable infrared pulses can easily be produced and detected electronically. Electric heaters that emit IR warm rooms quickly. Electric heaters have halogen hobs as they can emit much more IR.
Electrical heaters, cooking food, infrared cameras. remote controls/ hand held divices
Radio waves :radio:
Shorter wavelengths can carry more information and they spread out less. However, they have a shorter range due to increasing absorption of the atmosphere. <1m wavelength Tv masts as they carry more information, 1-100m local radio stations due to limmited range, 100m + national radiostations, longer range
:warning: 300000 - 3000 million Hz, can penetrate peoples bodies and heat internal body parts. More research needs to be done to find out if mobile phones are dangerous. Children have thinner skulls.
Television and radio
:warning: can heat internal parts of the body.
Have shorter wavelengths than radio waves and can pass through the atmosphere. Microwaves can penetrate into foods and are absorbed by water molecules and therefore heating it. The oven doesn't become hot because it has no water molecules. Spread out much less than radio waves so signal doesn't weaken
Satellite communications and cooking foods.