Watt – the SI unit of power; a joule/second

Wave – a disturbance that transfers energy from one point to another without imparting net motion to the medium through which it propagates

Wave function – a solution to the Schrödinger equation containing all the information that can be known about the particle the function describes (see equation 28.4)

Wave packet – a localized wave disturbance, resulting from combining a large number of waves of different wavelengths (see figure 28.9)

Wave surface – (Wavefront) that part of a wave defined by the points of constant phase

Wavelength – the distance between successive maxima, or wave crests

Weight – the gravitational force exerted on an object by a planet

Weightlessness – the condition that exist when an object is in free fall (the only force on the object is the gravity)

Wien displacement law – in the measurement of blackbody spectra, the wavelength of maximum intensity decreases with increasing temperature (see equation 27.3)

Work – the component of force in the direction of motion of an object times the distance through which it acts as an object is moved

Work-energy theorem – the work done on a particle by the net force acting on it is equal to the change in kinetic energy of the particle

Work function – the minimum amount of energy that must be acquired by an electron before it can escape from the surface of a material