STATEMENT-1 : Band gap in germanium is small.
because
STATEMENT-2 : The energy spread of each germanium atomic energy level is infinitesimally small.
because
STATEMENT-2 : The energy spread of each germanium atomic energy level is infinitesimally small.
- (A)Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1
- (B)Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-1✓ Correct
- (C)Statement-1 is True, Statement-2 is False
- (D)Statement-1 is False, Statement-2 is True
Answer: (B)
Solution
Statement-1 is true: germanium is a semiconductor with a relatively small band gap (~0.66 eV at room temperature). Statement-2 is false: in a solid like germanium, atomic energy levels broaden into energy bands due to interactions between closely packed atoms. The energy spread of each band is NOT infinitesimally small; rather, the bands are quite broad. The small band gap in Ge is due to the relatively small energy difference between the valence and conduction bands, not because of infinitesimally small energy spreads.
JEE Advanced · 2007 · 08 Apr 2007 · Paper 2 · Single correct option