A p-n photodiode is fabricated from a semiconductor with a band gap of 2.5 eV. It can detect a signal of wavelength ……..

Options

A. 4000 nm
B. 6000 nm
C. 4000 Å
D. 6000 Å

Answer

C

Explanation

4000 Å
`lambda_("max")=(hc)/(E )=(6.6xx10^(-34)xx3xx10^(8))/(2.5xx1.6xx10^(-19))=4950`Å
The wavelength obtained by the photodiode is less than `lambda_("max")` so it can detected to a signal having wavelength 4000 Å.