Physics Glossary – W

Weak Interaction

Is one of the four fundamental forces of nature. It is most commonly thought to be the cause of beta decay and the associated radioactivity. It is carried by the W bosons (W+ and W-) and Z bosons (Z0). The weak interaction affects: neutrinos charged leptons quarks The weak interaction enables all lepton and quark particles and antiparticles to interchange energy, mass and charge – effectively change into each other.

Wheatstone Bridge

Is a measuring instrument invented by Sir Charles Wheatstone. It is used to measure an unknown electrical resistance by balancing two legs of a ‘bridge circuit’, one leg of which includes the unknown component.

Wimhurst Machine

Is a device to measure atmospheric pressure is an historical electrostatic machine, a form of electrical generator for generating high voltages. It has a distinctive appearance, with two large contra-rotating discs mounted in a vertical plane, and a spark gap formed by two metal spheres. It was invented by James Wimshurst in 1883.

White Dwarf

Is a a star supported by electron degeneracy. A star like our Sun will become a white dwarf when it has exhausted its nuclear fuel. Near the end of its nuclear burning stage, such a star goes through a red giant phase and then expels most of its outer material (creating a planetary nebula) until only the hot (T > 100,000 K) core remains, which then settles down to become a young white dwarf.

Wien Displacement (Wien’s Law)

States that there is an inverse relationship between the wavelength of the peak of the emission of a blackbody and its temperature. Basically, the hotter an object is, the shorter the wavelength at which it will emit radiation.

Wollaston Prism

The device consists of two calcite or quartz prisms cemented such that they split into two beams which are mutually perpendicularly polarized by nearly equal amount in opposite directions. Named W. H. Wallaston.