PHYSICS DICTIONARY

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Wave Front

 The wave front of a wave is a surface at each point of which the vibrating particles are in same phase.

Wave Length

 Distance travelled by the wave in the time in which particle of medium completes one vibration.

                                              or

 Distance between two nearest particles in the same phase.

Wave Motion

It is a form of disturbance which travels through the medium due to repeated periodic motion of particles of medium about their mean positions. Wave motion, in general, refers to transfer of energy from one point to another point of medium. It is not matter that is propagated but it is only state motion of matter that is propagated. It is a form of dynamic condition that is propagated from one point to the other point in the medium.  

Wave

Wave is pattern and doesn’t have any physical existence. Wave motion comprises of patterns repeating at regular intervals and thus wave travels with uniform velocity.

Weidmann-Franz Law

The linear dependence of “ratio of thermal conductivity to electrical conductivity” on absolute temperature is known as Weidmann-Franz law. The ratio is directly proportional to absolute temperature.

 

Weight Percent (wt%)

Weight of a particular element relative to the total alloy weight.

Weld Decay

Intergranular corrosion that occurs in some welded stainless steels at regions adjacent to the weld.

Welding

 Process of permanently joining two similar metals by localized fusion by applying suitable heat and pressure is called as welding.

Wet Bulb Temperature

Wet-bulb temperature represents how much moisture the air can evaporate. This temperature is often measured with a common mercury thermometer that has the bulb covered with a water-moistened wick and with a known air velocity passing over the wick.

White Dwarf

They are stars which are fainter, possess small diameter, and are very dense compared to other stars of same mass. A white dwarf star is a mass of Helium at an extremely high temperature and under external compression. At its central temperature, Helium atoms are expected to be completely ionized and the star may be regarded as gas composed of Helium nuclei and electrons.

Wiedmann Franz Law

The ratio of thermal conductivity(K) to electrical conductivity σ is a constant (called Lorentz number) at a particular temperature for all the metals.

or

Weidmann–Franz discovered in 1853 that all good electrical conductors are also good thermal conductors. Ratio of K to σ is constant at a particular temperature for all the metals. Later Lorentz showed that this ratio is proportional to absolute temperature ‘T’.   K/σT= const=L; L is called as Lorentz number.

Wien’s Displacement Law

The wavelength of radiation emitted by a black body at any temperature is inversely proportional to absolute temperature of the body.

or

At any temperature, the energy of radiations of wavelength emitted by black body is directly proportional to fifth power of its absolute temperature.

Work

If the applied force on object leads to some displacement then it is said that work is done on object.

Work-Energy Theorem

The work done by the resultant net force acting on a body is equal to change in its kinetic energy.

 

Wrought Alloy

 A metal alloy that is relatively ductile and amenable to hot working or cold working during fabrication.