Electromagnetic waves

    Cards (31)

    • Radio waves are used for TV and radio signals.
    • Microwaves are used for satellite and mobile phone communications, and cooking food.
    • Infrared radiation is used in remote controls, night vision goggles, and heat-sensing cameras.
    • Visible light is used for fibre optic communications. It has a short wavelength. Hazard: too bright a light can damage the eyes.
    • Ultraviolet radiation is used for sterilisation of water and food, artificial sun tanning. Hazard: UV can damage skin cells and cause premature aging.
    • X-rays: used for medical imaging. Pass easily through flesh but not through denser materials like bone.
    • Gamma rays: very short wavelength.
    • electromagnetic waves are transverse waves
    • Why are electromagnetic waves not mechanical waves?
      They can travel through a vacuum (don't need a substance to travel through)
    • List the different types of wave in the electromagnetic spectrum in order of decreasing wavelength?
      radio, microwave, infrared, visible, ultraviolet, x-ray, gamma
    • which part of the EM spectrum can humans see?
      visible light
    • how are gamma waves be produced?
      changes in the nucleus of an atom, for example during radioactive decay
    • how can radio waves be produced?
      oscillations in an electric circuit
    • how can we detect radio waves?
      wave are absorbed and create an alternating current with the same frequency as the radio wave
    • what are radio waves used for?
      transmitting television, mobile phone, Bluetooth signals
    • what are microwaves used for?
      satellite communications, cooking food
    • why are x-rays used for medical imaging?
      they can pass through flesh but not bone
    • why are gamma rays used for treating cancer and sterilising medical equipment?
      high does kill cancer cells and bacteria
    • What is refraction?
      waves change speed and direction as they cross the boundary from one sustance to another
    • Radio waves have a wavelength of 1m - 10 000m
    • Radio waves can travel long distances and can be reflected off the surface of the earth.
    • Longer radio wave wavelengths can bend around obstructions to allow detection of signals when not in line of sight.
    • Gamma rays pass easily through the body. Used for cancer treatment to kill cancerous cells.
    • X-rays hazard: form of ionising radiation, can damage cells and cause cancer.
    • Microwaves have a wavelength of about 1cm.
    • Microwaves can pass through the Earth's atmosphere to reach satellites.
    • Microwaves can penetrate into food and are absorbed by water molecules inside food which vibrate and then heat the food.
    • Microwaves Hazard: they can penetrate the body and cause internal heating.
    • All hot objects emit infrared waves, sensors use these to create an image.
    • Infrared waves can transfer energy quickly to heat rooms.
    • Infrared Hazard: can damage or kill skin cells due to heating.
    See similar decks