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
