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A semiconductor shows an increase in electrical conductivity when it is exposed to electromagnetic radiation with wavelength less than 2480 nm. What is the band gap of the semiconductor, in eV?

1. 2.5 eV
2. 1.1 eV
3. 0.7 eV
4. 0.5 eV

Correct answer: 0.5 eV

Solution

Band gap Eg = hc/lambda = 1240 eV*nm / 2480 nm = 0.5 eV.

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