A circuit employs a silicon solar cell to detect flashes of light lasting 0.25 s. The smallest current the circuit can detect reliably is 0.32 μA .

Question

Assuming that all photons reaching the solar cell give their energy to a charge carrier, what is the minimum power of a flash of light of wavelength 570 nm that can be detected?

Attempt at solution:

Using Equation 1: f=c/wavelength

=(3.00*10^8m/s)/(570*10^-9m)=5.26HZ

And Equation 2: E=hf

Planck's Constant= h=6.63*10^-34J*s= 4.14*10^-15eV*s

E=(6.63*10^-34J*s)(5.26HZ)=3.49*10^-19

3.49*10^-19/0.25s=1.39*10^-18 W

I'm not sure where to factor in the
0.32 μA, but I know that the unit is suppose to be in W.

Answer 1

P = E/t