Question

In germanium the energy gap is about 0.75 eV. The wavelength of light which germanium starts absorbing is(a) 5000 Å(b) 1650 Å(c) 16500 Å(d) 165000 Å

Answer 1

i think it will be b

Answer 2

Energy gap = 0.75eV

E = hc/ γ

γ = hc/E

= 6.6× 10 raise to the power -34 × 3× 10 raise to the power 8/ 0.75×1.6×10 raise to the power -19

= 1.65× 10 raise to the power -6 m

= 16500Å

Thus, the germanium will start absorbing at the wavelength of 16500Å