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Electronics — JEE physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceJEE physicsElectronics1 Mark
Question
Assertion : If the temperature of a semiconductor is increased then it's resistance decreases.
Reason : The energy gap between conduction band and valence band is very small
✓

Answer

(a) In semiconductors the energy gap between conduction band and valence band is small $(\approx 1 \mathrm{eV})$. Due to temperature rise, electron in the valence band gained thermal energy and may jump across the small energy gap, goes in to the conduction band. Thus conductivity increases and hence resistance decreases.

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