A certain metal has a work function of f = eV. It is illuminated in vacuum by x 10^-6 W of light with a wavelength of l =  nm.

a) What is the minimum voltage needed to reduce the resulting photocurrent to zero?

V = V

b) How many photons per second are incident on the metal?

N = photons per second

c) For the photon flux in part b, what is the maximum possible photocurrent in amperes?

I_max = amperes

d) What is the cut off frequency for this metal?

f_c = Hz