The correct option is B 1.47×1010m−2s−1
Intensity of light falling Io=10−8W/m2
Wavelength of light λ=365×10−9 m
Absorption coefficient a=0.8
Thus intensity of light absorbed I=aIo=0.8×10−8 W/m2
Energy of one photon E=hcλ
So, number of photons absorbed per sq.meter per second N=IE=Iλhc
∴ N=(0.8×10−8)(365×10−9)(6.62×10−34)(3×108)= 1.47×1010 photons m−2s−1
Since one photon ejects one electron from the surface, so number of electron emitted is 1.47×1010 electrons m−2s−1.