em spectrum

what is it?

  • range of em waves arranged in order of their frequency & wavelength

  • hazards depend on their frequency

  • energy radiation is dependent on its frequency

    → higher frequency = higher energy radiation

  • energy formula — (energy) = h(frequency)

    → h = 6.63×10-34 Js

ionizing and non-ionizing radiation

  • non-ionizing radiation — insufficient energy to ionize

  • ionizing radiation — type of energy released by atoms that travels in a form of em waves

    → more dangerous to humans

em spectrum

  1. radio waves

    • longest wavelength, lowest frequency & energy

    • least dangerous

      → radio, television, wireless networks, RFID, bluetooth, wi-fi

      • may interfere w/ the atmosphere

      • easily disrupted & reflected by objects

  2. microwaves

    • 2nd longest wavelength, 2nd lowest frequency & energy

    • discovered by james clerk maxwell

      → heats food, passes through the ionosphere & connects to satellites

      • non-microwavable-safe plastic can cause harmful chemicals

      • can reduce nutritional value, uneven heating

  3. infrared waves

    • invisible to the human eye, produces heat

    • means “below red”

      → provides heat, used in remotes and televisions

      • may cause burns, eye damage

      • obstructed by physical barriers

  4. visible light

    • visible to the naked eye, ROYGBIV

      → comes from the sun, lasers, & light bulbs

      • potential eye & skin damage from overexposure

  5. ultraviolet rays

    • discovered by johann wilhelm ritter

    • emitted by the sun

      → produces vitamin d, used in sun tanning

      • damages skin

      • may cause skin cancer & premature aging

    1. UVA — 95% of earth’s solar UV

    2. UVB — affects epidermis, top layer of skin

    3. UVC — absorbed by atmosphere

  6. x-rays

    • 2nd shortest wavelength, 2nd highest frequency & energy

    • aka roentgen ray

      → creates images of bones & organs

      → used in dental imaging

      • may cause skin cancer, skin redness, hair loss

      • 2nd most ionizing

    1. soft x-ray — penetrates tissue & bones

    2. hard x-ray — mainly industrial applications, security

  7. gamma rays

    • shortest wavelength, highest frequency & energy

      → used in medical treatments, sterilization, quality control, radiotherapy for skin cancer, breeding new seed varieties

      • damages & kills cells

      • may cause burns & organ failure

      • most ionizing