electromagnetic radiation

Examples of electromagnetic radiation in the following topics:

• Electromagnetic Spectrum

  • The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation.
  • The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation.
  • The behavior of electromagnetic radiation depends on its wavelength.
  • Electromagnetic radiation interacts with matter in different ways in different parts of the spectrum.
  • At the same time, there is a continuum containing all these different kinds of electromagnetic radiation.

• The Photoelectric Effect

  • The photoelectric effect is the propensity of high-energy electromagnetic radiation to eject electrons from a given material.
  • In the photoelectric effect, electrons are emitted from matter (metals and non-metallic solids, liquids, or gases) as a consequence of their absorption of energy from electromagnetic radiation of high frequency (short wavelength), such as ultraviolet radiation.
  • When electromagnetic radiation interacts with an atom, it can excite the electron to a higher energy level, which can then fall back down, returning to the ground state.
  • For a given metal, there exists a certain minimum frequency of incident radiation below which no photoelectrons are emitted.
  • However, if just the intensity of the incident radiation is increased, there is no effect on the kinetic energies of the photoelectrons.

• Air Pollution

  • The greenhouse effect: an elevation in the Earth's surface temperature due to the absorption of electromagnetic radiation by atmospheric gases.

• Modes of Radioactive Decay

  • Radioactive decay occurs when an unstable atomic nucleus loses energy by emitting energy in the form of emitted particles or electromagnetic waves, called radiation.
  • Likewise, gamma radiation and X-rays were found to be similar high-energy electromagnetic radiation.
  • Some decay reactions release energy in the form of electromagnetic waves called gamma rays.
  • Gamma radiation (γ) is part of the electromagnetic spectrum, just like visible light.
  • Gamma radiation has no mass or charge.

• Planck's Quantum Theory

  • Electromagnetic (EM) radiation is a form of energy with both wave-like and particle-like properties; visible light being a well-known example.
  • The wavelength or frequency of any specific occurrence of EM radiation determine its position on the electromagnetic spectrum and can be calculated from the following equation:
  • For each metal, there is a minimum threshold frequency of EM radiation at which the effect will occur.
  • According to Planck: E=h$\nu$, where h is Planck's constant (6.62606957(29) x 10-34 J s), ν is the frequency, and E is energy of an electromagnetic wave.
  • Planck (cautiously) insisted that this was simply an aspect of the processes of absorption and emission of radiation and had nothing to do with the physical reality of the radiation itself.

• Introduction

  • As noted in a previous chapter, the light our eyes see is but a small part of a broad spectrum of electromagnetic radiation.
  • Consequently, virtually all organic compounds will absorb infrared radiation that corresponds in energy to these vibrations.
  • Liquids are usually examined as a thin film sandwiched between two polished salt plates (note that glass absorbs infrared radiation, whereas NaCl is transparent).

• The Electromagnetic Spectrum

  • The visible spectrum constitutes but a small part of the total radiation spectrum.
  • Most of the radiation that surrounds us cannot be seen, but can be detected by dedicated sensing instruments.
  • This electromagnetic spectrum ranges from very short wavelengths (including gamma and x-rays) to very long wavelengths (including microwaves and broadcast radio waves).
  • The bottom equation describes this relationship, which provides the energy carried by a photon of a given wavelength of radiation.

• The Bohr Model

  • In these orbits, an electron's acceleration does not result in radiation and energy loss as required by classical electromagnetic theory.
  • Electrons can only gain or lose energy by jumping from one allowed orbit to another, absorbing or emitting electromagnetic radiation with a frequency (ν) determined by the energy difference of the levels according to the Planck relation.
  • However, unlike Einstein, Bohr stuck to the classical Maxwell theory of the electromagnetic field.
  • Quantization of the electromagnetic field was explained by the discreteness of the atomic energy levels.
  • But for small n (or large k), the radiation frequency has no unambiguous classical interpretation.

• Nuclear Fission

  • The electromagnetic force causes the repulsion between like-charged protons.
  • The strong nuclear force acts to hold all the protons and neutrons close together, while the electromagnetic force acts to push protons further apart.
  • In atoms with small nuclei, the strong nuclear force overpowers the electromagnetic force.
  • As the nucleus gets bigger, the electromagnetic force becomes greater than the strong nuclear force.
  • These nuclei are called unstable, and this instability can result in radiation and fission.

• Acute Radiation Damage

  • Acute radiation syndrome or damage describes health effects present within 24 hours of exposure to high amounts of ionizing radiation.
  • Acute radiation syndrome, also known as radiation poisoning, radiation sickness, or radiation toxicity, is a constellation of health effects that are present within 24 hours of exposure to high amounts of ionizing radiation, which can last for several months.
  • Radiation sickness is caused by exposure to a large dose of ionizing radiation over a short period of time, typically greater than about 0.1 Gy/h.
  • The onset and type of symptoms depends on the radiation exposure.
  • These diseases are sometimes referred to as radiation sickness, but they are never included in the term acute radiation syndrome.