Besides the matrix-tree theorem, he developed a set of laws governing the continuous spectra of hot solid objects, emission-line spectra of gases, and the absorption spectra that result when hot objects are viewed through a cooler gas.
A generalization of Cayley's theorem named for this man gives the number of nonidentical spanning trees of a given graph as a cofactor of the admittance matrix . Besides the matrix-tree theorem, he developed a set of laws governing the continuous spectra of hot solid objects, emission-line spectra of gases, and the absorption spectra that result when hot objects are viewed through a cooler gas. With Robert Bunsen, he developed emission spectroscopy and discovered cesium and rubidium, while a set of relations governing the sum of currents and potentials in various branches of a circuit.  For 10 points, name this German physicist who used conservation of charge and energy to develop his namesake loop and junction rules.
A generalization of Cayley's theorem named for this man gives the number of nonidentical spanning trees of a given graph as a cofactor of the admittance matrix .
Gustav Robert {Kirchoff}