# Einstein

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## Einstein

**Albert.**1879--1955, US physicist and mathematician, born in Germany. He formulated the special theory of relativity (1905) and the general theory of relativity (1916), and made major contributions to the quantum theory, for which he was awarded the Nobel prize for physics in 1921. He was noted also for his work for world peace

## Einstein

a unit of energy of electromagnetic radiation in the optical range. The einstein, which is used in photochemistry, is equal to *N _{A}hv*, where

*N*is Avogadro’s number and

_{A}*hv*is the energy of the photon. It was named in honor of Albert Einstein and is abbreviated E. When a radiant energy of 1 E is absorbed, the photochemical conversion of 1 mole of the substance should occur, according to Einstein’s law of photochemical equivalence. It follows from the definition of the einstein that the dimension of the unit is determined by the radiation frequency (

*v*) (

*h*is Planck’s constant).

## einstein

[′īn‚stīn] (physics)

A unit of light energy used in photochemistry, equal to Avogadro's number times the energy of one photon of light of the frequency in question.