Question

(9) When radiation interacts with a semiconductor resulting in stimulated emission, the

wavelength of the output radiation is (   )

(A) Half the wavelength of the incident radiation

(B) Two times the wavelength of the incident radiation

(C) May be higher or lower than that of the incident radiation, depending on the material

(D) Same as the wavelength of the incident radiation

Answer 1

Answer D

When radiation interacts with a semiconductor resulting in stimulated emission, the

wavelength of the output radiation is Same as the wavelength of the incident radiation

Explanation

When an electron is in a different energy level of the fundamental level and returns to the ground state through an incident photon(radiation), a new photon is generated with exactly the same frequency, direction and phase to the incident photon. This process, known as stimulated emission.

Since the frequency of new photon is same as incident photon, it means wavelength of output photon (output radiation) is same as incident photon(input radiation) because

λ= c/f , c is speed of light (constant=3x10⁸ m/s) , f is frequency and  λ is wavelength

So if f(frequency) is same then  λ(wavelength ) is also same because product of  λ and f is constant .

λf =c , c = speed of light = 3x10⁸ m/s