Machine-translated by Google. Questions are authored in English.
Top

Discussion

The relative permittivity of air at ordinary pressure is taken as unity because

  • A.air contains no molecules capable of polarising at all
  • B.air is a conductor and therefore has no permittivity
  • C.the permittivity of a gas is defined to be exactly one
  • D.it exceeds unity by only a few parts in ten thousand

Answer: D

The measured value is about 1.00059, so treating air as a vacuum introduces an error far smaller than that of any ordinary measurement. It does rise with pressure, which is why compressed gas capacitors and gas-insulated switchgear behave measurably differently from air-filled ones.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.