chemistry
posted by schoolgirl .
(b) Calculate the absorption edge of this material. Express your answer as a wavenumber in units of inverse meters.

What material?

50 g Si doped with 27g Sb

Here is the full question:
(a) Silicon (50 g) has been doped with 27 mg of antimony (Sb). Determine the concentration of free charge carriers (carriers/cm3) at room temperature in this material.
Answer for a=6.22*10^18
(b) Calculate the absorption edge of this material. Express your answer as a wavenumber in units of inverse meters. 
a) 6.22*10^18
b)wavenumber= Eg / hc
Eg(Silicon band energy)= 1.11 eV (to joules)
h=6.6*10^34
c=3*10^8
wavenumber= Eg*1.6*10^19 / hc = 896969.69 
8.97*10^5