Faraday shield

Examples of Faraday shield in the following topics:

• Electrostatic Shielding

  • Electrostatic shielding is the phenomenon that occurs when a Faraday cage blocks the effects of an electric field.
  • Electrostatic shielding is the phenomenon that is observed when a Faraday cage operates to block the effects of an electric field.
  • When an external electric field operates on a Faraday cage, the charges within the cage (which are mobile, as the cage is a conductor) rearrange themselves to directly counteract the field and thus "shield" the interior of the cage from the external field
  • They can, however, shield the interior from external magnetic radiation provided that the mesh is smaller than the wavelength of the radiation and that the shield is sufficiently thick.
  • Elevators can act as unintended Faraday cages, shielding cell phones and radios from signal from the outside.

• Van de Graff Generators

  • The sphere acts as a Faraday shield, shielding the upper roller and comb from the electric field produced by charges on the outside of the sphere.

• Conductors and Fields in Static Equilibrium

  • This occurrence is similar to that observed in a Faraday cage, which is an enclosure made of a conducting material that shields the inside from an external electric charge or field or shields the outside from an internal electric charge or field.

• Multielectron Atoms

  • The shielding theory also explains why valence shell electrons are more easily removed from the atom.
  • The size of the shielding effect is difficult to calculate precisely due to effects from quantum mechanics.
  • A multielectron atom with inner electrons shielding outside electrons from the positively charged nucleus

• Faraday's Law of Induction and Lenz' Law

  • The direction (given by the minus sign) of the EMF is so important that it is called Lenz' law after the Russian Heinrich Lenz (1804–1865), who, like Faraday and Henry, independently investigated aspects of induction.
  • Faraday was aware of the direction, but Lenz stated it, so he is credited for its discovery .

• Radiation from Food

  • Radioactive material must be monitored and carefully stored to shield workers and the environment from its gamma rays.
  • During operation this is achieved using concrete shields.
  • With most designs the radioisotope can be lowered into a water-filled source storage pool to allow maintenance personnel to enter the radiation shield.
  • X-ray systems also rely on concrete shields to protect the environment and workers from radiation.

• Induced EMF and Magnetic Flux

  • The apparatus used by Faraday to demonstrate that magnetic fields can create currents is illustrated in the following figure.

• Avogador's Number

• Maxwell's Predictions and Hertz' Confirmation

  • Combining the work of physicists including Oersted, Coulomb, Gauss, and Faraday, and adding his own insights, James Clerk Maxwell developed a complete and overarching theory showing electric and magnetic forces are not separate, but different forms of the same thing: the electromagnetic force.

• Transformers

  • The type of transformer considered here is based on Faraday's law of induction, and is very similar in construction to the apparatus Faraday used to demonstrate that magnetic fields can create currents (illustrated in ).