The Correct Answer is Option (D)

Photodiodes are preferably operated in reverse bias condition for light intensity measurement because it increases the width of depletion layer, therefore both are correct but not the correct explanation.

The Correct Answer is Option (B)

Solar cell characteristics

The Correct Answer is Option (D)

A photodiode is reverse biased. When light falling on it produces charge carriers, the fractional change, in minority carriers is high since the original current is very small.

$R$ will be minimum when $R_L$ is infinitely large, so

$R_{\text{Zener }}=\frac{8}{25\times {10}^{-3}}=320\mathrm{\Omega }$

So $\frac{R}{R_{\text{Zener }}}=\frac{12}{8}$

$R=\frac{12}{8}\times 320=480\mathrm{\Omega }$

$i_s=\frac{60}{4\times {10}^3}=15\times {10}^{-3}=15$ mA

$i_L=\frac{60}{10\times {10}^3}=6$ mA

$I_z=i_s-i_L=9$ mA