He was a physicist who made important contributions to the theory of circuits using topology and to elasticity. Kirchhoff's laws, announced in 1854, allow calculation of currents, voltages and resistances of electrical circuits extending the work of Ohm. His work on black body radiation was fundamental in the development of quantum theory.
His work on spectrum analysis led on to a study of the composition of light from the Sun. Kirchhoff was the first to explain the dark lines in the Sun's spectrum as caused by absorbsion of particular wavelengths as the light passes through a gas. This started a new era in astronomy.
In 1875 he was appointed to the chair of mathematical physics at Berlin.
Disability meant he had to spend much of his life on crutches or in a wheelchair.
His best known work is the four volume masterpiece Vorlesungen über
mathematische Physik (1876-94).
The URL of this page is:
http://www-history.mcs.st-andrews.ac.uk/history/Mathematicians/Kirchhoff.html