electromagnetic spectrum

• Electromagnetic spectrum is a continuous spectrum of waves which includes the visible spectrum
• at one end of the spectrum, the waves have a very long wave length and low frequency while at the other end the waves have a very short wavelength and high frequency
• the properties of the electromagnetic spectrum: 1. they all transfer energy 2. they all are transverse wave 3. they all travel at 300.000.000 m/s. the speed of light in a vaccum (free space). 4. they can be reflected and refracted
• types of electromagnetic radiation: radio waves, microwaves, infrared radiation, visible light, ultra violet radiation, x radiation and gamma rays
• radio waves - used to transmit information from satellites or TV signals
• microwaves - used by mobile phones and radar systems
• infrared radiation - heaters use this type of radiation to warm up objects
• infrared radiation - used in device like remote control and thermal cameras
• microwaves - used to cook and heat food and also used for communications such as wifi and cellphones
• radio wave have long wave length and short frequency
• infrared radiation is sometimes called as ''heat radiation''
• x-rays are used to see inside the body without cutting it open
• gamma rays are used in cancer treatment
• Infrared radiation - used to see people on dark
• microwave and infrared is used to cooking
• radio wave, visible light and microwave is used in communicating
• gamma rays is produced during nuclear radiation
• microwave oven cook food much more quickly than normal ovens because the water molecules in the food absorbs the microwave and becomes very hot. The food therefore cooks through out rather than just from the outside
• x-rays is used to check for bones because x rays can pass easily through soft body tissue but cannot pass through bones. as a result, x rays pictures can be taken to check patients bone
• it is important not to damage the ozone layer around the earth because the ozone layer in the earth's atmosphere absorbs large quantities of the sun's UV radiation. The amount of ozone is decreasing due to pollution. this may lead to increase number of skin cancers in the future
• food stays fresher for longer after it has been exposed to gamma rays because gamma rays have high penetrating rays and can cause damage to living cells. they can kill microorganisms so that food will keep for longer
• x rays can cause cancer, precautions: lead screening
• uv light can cause sunburn, blistering, skin cancer and blindness precautions: protective goggles/glasses and skin creams
• infrared can cause skin burn, precautions: operate only over small distance
• microwave can cause harm the brain, precautions: dont overuse the mobile phone
• gamma rays can cause cancer, precautions: lead screens, boxes and aprons