Transfer of Energy by EM Waves (AQA GCSE Combined Science: Trilogy: Physics): Revision Note

Transfer of Energy by EM Waves

• Electromagnetic (EM) waves carry energy and so can transfer energy from one point to another point

• EM radiation is an energy transfer pathway

• EM waves with a shorter wavelength carry a higher energy

  • This includes UV, X-rays and gamma rays

• The higher the energy of the EM wave, the more dangerous it is

Energy Transfer by Microwaves

• Water molecules absorb certain wavelengths of microwave radiation

• Therefore, microwave ovens transfer energy by radiation to the thermal store of the food placed inside it

Energy transfer in a microwave oven

Energy Transfer by Infrared

• All hot objects emit infrared radiation

• The emitted waves can then be absorbed by other objects, warming them up

• Therefore energy is transferred by radiation to the thermal store of the object (and the surroundings)

Energy Transfers from the Sun

• The Sun emits several types of EM radiation, including:

  • Visible light waves allow living creatures to see

  • Infrared waves heat up the Earth

  • Ultraviolet waves cause suntans and sunburn

• Energy from the Sun is transferred by radiation