What is a Faraday cage?

What is a Faraday cage?

• A. Shields whatever is inside of it from electromagnetic radiation
• B. A device that creates strong electric fields
• C. A material that conducts heat
• D. A type of insulator used in cables

Answer: (A)

A Faraday cage is a conductive enclosure that blocks external electric fields and electromagnetic radiation from reaching the space inside it. When an external field hits a conductor, free electrons rearrange themselves on the surface so the interior field is canceled out. For static fields this cancellation is essentially complete; for changing fields, the shielding works best when the enclosure is continuous and any openings are much smaller than the wavelength of the radiation. A metal box or a fine metal mesh around devices is a common example, which can stop signals like radio waves or phone signals from getting in or out. It’s not about creating strong electric fields, nor about conducting heat per se, and it’s not an insulating material used in cables.

A Faraday cage is a conductive enclosure that blocks external electric fields and electromagnetic radiation from reaching the space inside it. When an external field hits a conductor, free electrons rearrange themselves on the surface so the interior field is canceled out. For static fields this cancellation is essentially complete; for changing fields, the shielding works best when the enclosure is continuous and any openings are much smaller than the wavelength of the radiation. A metal box or a fine metal mesh around devices is a common example, which can stop signals like radio waves or phone signals from getting in or out. It’s not about creating strong electric fields, nor about conducting heat per se, and it’s not an insulating material used in cables.