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
Bit-paired keyboard but bit-paired keyboards have (rows 10, 11, and 13) instead of and are missing the key, as these are shifted values of digits. This is the complete set of symbols on the Model 33; it is notably missing though these are present on other bit-paired keyboards. On both bit-paired and typewriter-paired keyboards, are paired (rows 11, 12, and 13), but on bit-paired keyboards are paired and is an unpaired key, while on typewriter-paired keyboards and are shifted digits, while are paired and is paired with . In the US, bit-paired keyboards continued to be used into the 1970s, including on