Physics Glossary – B


A device to measure atmospheric pressure.

Balmer Series

A series of sharp spectral lines in the hydrogen spectrum. Named after J.J. Balmer.


A unit of pressure nearly identical to the atmosphere unit. One bar = 750.062 torr = 0.9869 atm = 100,000 Pa.

Becquerel (Bq)

Is a derived SI unity of radioactivity. 1 Bq one atom per second will decay. Named after Antoine Henri Becquerel.

Beta Decay

A radioactive process in which a neutron changes into a proton and emits an electron and an anti-neutrino.

Bimetallic Strip

A strip of two metals joined together and as different metals will expand and contract at different rates, the strip will buckle with a change in temperature. Used in thermostats.

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