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?
A)
599 nm
B)
639 nm
C)
959 nm
D)
873 nm
E)
995 nm
Question 2
Two systems are in thermal equilibrium. The two systems are at the same
A)
pressure.
B)
volume.
C)
height.
D)
pressure and temperature.
E)
temperature.