The Planck constant shows the constant relationship between a photon's energy and its wavelength. Quantum mechanics also uses the same value to describe the sizes of quanta. The Planck constant is named after Max Planck and has a value of approximately 6.62606896 x 10^(-34) joule seconds. This value is so small because it is related to the energy of a single photon. The Planck constant is used extensively in physics, especially quantum mechanics.

Define the Planck constant mathematically. This can be shown as h = E/v where "h" is the Planck constant, "E" is the energy of a photon and "v" is the frequency of its associated wave. The Planck constant is therefore measured in units of energy "x" time.

Use the Planck constant to calculate a photon's energy from its wavelength. Using the definition of the Planck constant h = E/v, we have E = hv. The frequency "v" of a photon can be given as v = c/y, where "c" is the speed of light and "y" is the photon's wavelength. We therefore have E = hc/y.

Calculate the reduced Planck constant from the Planck constant. Wavelength frequency is typically measured in cycles per second but angular frequency uses radians per second. This conversion can be shown as hr = h/2Pi, where "hr" is the reduced Planck constant.

Calculate an electron's energy for a given energy level with the Bohr model. This equation is given as En = hcR/n^2 where "En" is the energy of the electron, "h" is the Planck constant, "R" is the Rydberg constant and "n" is the energy level.

Calculate Avogadro's number with the Planck constant. This is given as Na = MuAr(e)ca^2/2Rh where "Na" is Avogadro's number, "Mu" is the molar mass constant, "Ar(e)" is the relative atomic mass of the electron, "a" is the fine structure constant and "R" is the Rydberg constant.