Deviation from linearity in relationships between composition and this quantity occurs in its namesake “bowing.” The Kohn–Sham equations consistently underestimate the “fundamental” type of this quantity due to the derivative discontinuity. The Shockley–Queisser limit is the maximum of a plot of efficiency versus this quantity. This quantity can be tuned in perovskites by altering (10[2])halide concentrations, and tandem cells stack layers with different values of this quantity. Since the crystal momentum changes upon excitation, silicon has the “indirect” form of this quantity. This quantity determines the wavelength of an LED, and is around 3 electron volts for blue ones. Insulators have high values of, (10[1]-5[1])for 10 (10[1])points, (10[1])what quantity, (10[1]-5[1])the energy range that separates “valence” and “conduction” electrons in a solid? ■END■ (10[1]0[1])