EM spectrum

• what are the 7 EM waves?

  radio waves, micro waves, infrared, visible light, ultraviolet, x-rays, gamma
• which EM wave has the longest wavelength?

  radio waves
• which EM wave has the highest frequency?

  gamma rays
• what do all EM waves do, in terms of energy?

  transfer energy from a source to an absorber
• what are the dangers of x-rays and gamma rays?

  they are ionising, they can cause mutations and damage cells (leading to cancer)
• what are the dangers of radio waves?

  heating of biological tissue and body temperature
• what are the dangers of microwaves?

  when absorbed into the body, it causes the heating of cells
• what are the dangers of infrared?

  can cause burns if the skin gets too hot
• what are the dangers of ultraviolet?

  can cause damage to cells on the surface of the skin, leading to skin cancer and eye damage (blindness)
• what happens to EM waves as the temperature of an object increases?

  the intensity of every emitted wavelength increases
• what is peak wavelength?

  the wavelength with the highest intensity
• what causes peak wavelength to decrease?

  when the intensity increases more rapidly for shorter wavelengths than longer wavelengths
• what happens if the average power that the object absorbs is more than the average power that it radiates?

  the object heats up
• in terms of EM radiation, when does an object cool down?

  when the average power radiated is larger than the average power absorbed
• what is the radiation from the sun absorbed and reflected by?

  the Earth's atmosphere, clouds, and surface
• how can changes to the Earth's atmosphere cause a change to the Earth's overall temperature?

  if the atmosphere starts to absorb more radiation without emitting the same amount, the overall temperature will rise until absorption and emission are equal again
• what causes a decrease in local temperature at night?

  radiation emitted by the atmosphere, clouds, and the Earth's surface
• what are EM waves made up of?

  oscillating electric and magnetic fields
• what happens to the energy carried by radio waves?

  it is transferred to the electrons in the material of the reciever
• what are radio waves mainly used for ?

  communication and broadcasting
• which EM waves are satellites used by?

  radio waves and microwaves
• what happens insides of microwave ovens?

  the microwaves are absorbed by water molecules in food
• what are the uses of infrared cameras?

  used to detect infrared radiation and monitor temperature
• what are uses of infrared radiation?

  infrared cameras, thermal imaging, infrared sensors, electric heaters, and transferring information
• what are uses of visible light?

  digital cameras, photographic film, light
• what are the uses of ultraviolet?

  fluorescence, fluorescent lights, security pens, bank notes, passports, and sterilising water
• what are the uses of x-rays?

  medical imaging
• what are the uses of gamma rays?

  sterilise medical instruments, medical imaging, and cancer treatments