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In a metal:
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- the electrical conduction is by electrons and holes
- with rise in temperature, the conductivity decreases
- the conduction band is empty
- there is small energy gap between two bands
Correct Option: B
With rise in temperature, the conductivity decreases which can be easily explained by equation,
σ = nq µn
where, σ = conductivity of a metal
n = no. of free electrons in a metal
q = charge of electron
µn = mobility of electron.
With rise in temperature there will be no effect on n and q. However as temperature rises, ions present in the crystal lattice becomes vibrate, resulting decreases in mobility, µn. Because mobility of an electron defines as how freely electron moves in a crystal. Hence conductivity of metal decreases with rise in temperature.
