At room temperature (300 K) the effective density of states in the valence band is 2.66 1019 cm-3 for silicon and 7 1018 cm-3 for gallium arsenide.

At room temperature (300 K) the effective density of states in the valence band is2.66 × 1019 cm-3 for silicon and 7 × 1018 cm-3 for gallium arsenide. Find thecorresponding effective masses of holes. Compare these masses with thefree-electron mass