Consider a `20W` bulb emitting light of wavelength `5000Å` and shinning on a metal surface kept at a distance `2m`. Assume that the metal surface has work function of `2eV` and that each atom on the metal surface can be treated as a circular disk of radius `1.5Å`

Options

A. Number of photon emitted by bulb is `5xx10^(19)` per second
B. Time required by atomic disk to receive energy equal to work function of metal is `22.4` sec
C. Number of photon received by disk to receive `2eV` energy is 4
D. Number of photons emitted by bulb is `5xx10^(17)` per sec

Answer

A

Explanation

`(dN)/(dt)=P/((hc//lamda))=5xx10^(19)//s`
`(hc)/(lamda)=2.49V gt W_(0):` Yes.