Monochromatic light of frequency f1 is incident on a photo cell and the stopping potential is found to be V1. What is the new stopping potential of the cell if it is radiated by monochromatic light of frequency f2?
Answer & explanation
Correct answer: option 1
$eV_1 = hf_1 – \phi$
$eV_2 = hf_2 – \phi$
$e(V_1 – V_2) = h (f_1 – f_2)$
$V_1 – V_2 =\frac{h}{e}(f_1 – f_2)$
$V_2 =V_1 +\frac{h}{e}(f_2 – f_1)$