Semiconductors: the Energy Gap Between the Valence and Conduction Bands

Multiple Choice

Semiconductors: The energy gap between the valence and conduction bands in a certain semiconductor is 1.25 eV. What is the threshold wavelength for optical absorption in this substance? (c = 3.00 × 10⁸ m/s, 1 eV = 1.60 × 10^-19 J, h = 6.626 × 10^-34 J ∙ s)

A) 599 nm
B) 639 nm
C) 959 nm
D) 873 nm
E) 994 nm