The energy gap between the valence band and the conduction band is largest in
Correct answer: C. an insulator
- A. a conductor
- B. a semiconductor
- C. an insulator
- D. all three equally
Explanation
An insulator has a gap of several electron volts, far more than thermal energy can supply, so almost no electrons reach the conduction band. A semiconductor's gap is about 1 eV, small enough for a useful number to cross, and in a conductor the bands overlap so there is effectively no gap at all. This single picture explains the huge range of electrical behaviour in solids.
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About PN Junction
A PN junction forms when p type and n type semiconductor regions meet, creating a depletion layer and a potential barrier. The topic covers forward and reverse bias, diode current voltage characteristics, breakdown and rectification, while distinguishing an ordinary junction diode from a transistor formed from multiple junctions.
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