Planck's law In 1880, André-Prosper-Paul Crova published a diagram of the three-dimensional appearance of the graph of the strength of thermal radiation as a function of wavelength and temperature. He determined the spectral variable by use of prisms. He analyzed the surface through what he called "isothermal" curves, sections for a single temperature, with a spectral variable on the abscissa and a power variable on the ordinate. He put smooth curves through his experimental data points. They had one peak at a spectral value characteristic for the temperature, and fell either side of it towards the horizontal axis. Such spectral sections are
Graph of a function height, radius, and angle assign precise locations of the points. Fibre bundles are not Cartesian products, but appear to be up close. There is a corresponding notion of a graph on a fibre bundle called a section. See List of graphing software Graph of a function In mathematics, the graph of a function "f" is, formally, the set of all ordered pairs , such that "x" is in the domain of the function "f", and, in practice, the graphical representation of this set. If the function input "x", and the values "f"("x"), are real numbers, the graph is a two-dimensional