$kT=0\mathrm{.}026eV$ at $300K,Si{n}_i={10}^{10}c{m}^{-3}$ at $300K,S{i}_g=1\mathrm{.}1eV,q=1\mathrm{.}6{10}^{-19}C,h=6\mathrm{.}63{10}^{-34}J-s,{}_0=8\mathrm{.}85{10}^{-14}$

$\frac{F}{c}m,$ Relative permittivity of $Si=11\mathrm{.}8,c=3{10}^{10}c\frac{m}{s},I_0=qA(D_p\frac{p_n}{L_p}+D_n\frac{n_p}{L_n})$

$(19$ p$)$ A laser with a power output of $100$ mW $($wavelength $=532nm)$ is focused on a silicon $($Si$)$ sample of $2m$ thickness. The absorption coefficient of the sample is $=1{10}^{4}c{m}^{-1}.$

$($a$)(5$ p$)$ Find the number of photons entering the silicon surface per second.

$($b$)(6$ p$)$ Find the number of photons leaving the silicon sample per second.

$($c$)(8p)$ The power delivered to the Si sample as heat.