Question

Calculate the number of electrons is the number of holes are 15*10^10?

(a) 15*10^10

(b) 1.5*10^8

(c) 1.5*10^9

(d) 1.5*10^10

This question was addressed to me in a job interview.

My query is from Charge Densities in a Semiconductor impurities topic in section Conduction in Semiconductors of Electronic Devices & Circuits

Answer 1

Correct answer is (c) 1.5*10^9

To explain: n*p=(1.5*10^10)^2

                       n*15*10^10=1.5*1.5*10^10*10^10

           n=1.5*10^9 electrons.