Solid angle orientation formula_9, and distance from the viewer as: where the surface area of a sphere is . The solid angle of a cone with its apex at the apex of the solid angle, and with apex angle 2, is the area of a spherical cap on a unit sphere For small such that , this reduces to the area of a circle . The above is found by computing the following double integral using the unit surface element in spherical coordinates: This formula can also be derived without the use of calculus. Over 2200 years ago Archimedes proved that the
Einstein solid Walther Nernst learned of Einstein's 1906 paper on specific heat, he was so excited that he traveled all the way from Berlin to Zürich to meet with him. The heat capacity of an object at constant volume "V" is defined through the internal energy "U" as formula_3, the temperature of the system, can be found from the entropy To find the entropy consider a solid made of formula_5 atoms, each of which has 3 degrees of freedom. So there are formula_6 quantum harmonic oscillators (hereafter SHOs for "Simple Harmonic Oscillators"). Possible energies of an SHO are given by or, in