14.3 Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separated by energy band gap respectively equal to (Eg)C, (Eg)Si and (Eg)Ge. Which of the following statements is true?

(1) (Eg)Si < (Eg)Ge < (Eg)C

(2) (Eg)C < (Eg)Ge > (Eg)Si

(3) (Eg)C > (Eg)Si > (Eg)Ge

(4) (Eg)C = (Eg)Si = (Eg)Ge

Hint: Comparing the energy gap of Si, C and Ge using band theory of solids.
Step 1: Identify the energy band gap for given elements.

For three given elements, the energ band gap of carbon is the maximum and that of germanium is least.
Thus, option(3) is correct.
Carbon is insulator and hence the value of energy band gap is maximum for it. Of the other two semiconductors, the value of energy band gap for germanium is lesserRead more on Sarthaks.com - https://www.sarthaks.com/636060/carbon-silicon-germanium-have-four-valence-electrons-each-these-characterised-valence
Carbon is insulator and hence the value of energy band gap is maximum for it. Of the other two semiconductors, the value of energy band gap for germanium is lesser.Read more on Sarthaks.com - https://www.sarthaks.com/636060/carbon-silicon-germanium-have-four-valence-electrons-each-these-characterised-valence
Carbon is insulator and hence the value of energy band gap is maximum for it. Of the other two semiconductors, the value of energy band gap for germanium is lesser.Read more on Sarthaks.com - https://www.sarthaks.com/636060/carbon-silicon-germanium-have-four-valence-electrons-each-these-characterised-valence
Carbon is insulator and hence the value of energy band gap is maximum for it. Of the other two semiconductors, the value of energy band gap for germanium is lesser.Read more on Sarthaks.com - https://www.sarthaks.com/636060/carbon-silicon-germanium-have-four-valence-electrons-each-these-characterised-valence