the branch of physics concerned with electromagnetic phenomena
magnetism produced by an electric current; "electromagnetism was discovered when it was observed that a copper wire carrying an electric current can magnetize pieces of iron or steel near it"
the lagging of an effect behind its cause; especially the phenomenon in which the magnetic induction of a ferromagnetic material lags behind the changing magnetic field
memory device consisting of a long thin plastic strip coated with iron oxide; used to record audio or video signals or to store computer information; "he took along a dozen tapes to record the interview"
having an indicated pole (as the distinction between positive and negative electric charges); "he got the polarity of the battery reversed"; "charges of opposite sign"
the basic unit of luminous intensity adopted under the Systeme International d'Unites; equal to 1/60 of the luminous intensity per square centimeter of a black body radiating at the temperature of 2,046 degrees Kelvin
examine eggs for freshness by holding them against a light
marked by qualities giving the power to produce an intended effect; "written propaganda is less efficacious than the habits and prejudices...of the readers"-Aldous Huxley; "the medicine is efficacious in stopping a cough"