Assertion: A `P-N` photodiode is made from a semiconductor for which `E_(g)=2.8 eV`. This photo diode will not detect the wavelength of `6000 nm`.
Reason: A `PN` photodiode detect wavelength `lambda` if `(hc)/(lambda)gtE_(g)`.

Options

A. If both the assertion and reason are true and reason is a true explantion of the assertion.
B. If both the assertion and reason are true but the reason is not true the correct explantion of the assertion.
C. If the assertion is true but reason false
D. If both the assertion and reason are false.

Answer

A

Explanation

For detection of a particular wavelength `(lambda)` by a `PN` photo diode, energy of incident light `gtE_(g) implies (hc)/(E_(g))gt lambda`
For
`E_(g)=2.8 eV, (hc)/(E_(g)) =(6.6xx10^(-34)xx3xx10^(8))/(2.8xx1.6xx10^(-19))=441.9 nm`
i.e., `(hc)/(E_(g)) lt6000 nm`, so diode will not detect the wavelength of `6000Å`.