AP EAMCET Engineering 20 Apr 2019 Shift 1 Paper

In a p-type semiconductor the donor level is at 50 meV above the valen ce band. To produceone electron, the maximum wavelength of light photon required is
(Planck's constant = 6.6 x 10−34 J-s and speed of light in vacuum = 3 × 10ms−1)