A photoelectric experiment is performed where green light with a wavelength of 546.1 nm is shined on a metal plate, creating a photocurrent from it to a collector plate. When the potential difference between the metal plate and the collector is increased to a magnitude of 0.728 V, the photocurrent goes to zero—in other words, this is the stopping potential. What is the work function (in eV) for this metal?

Explanation:

We can use the work function equation for a photoelectric experiment:

So we will have:

I hope it helps you!

The work function is

Explanation:

   From the question we are told that

        The wavelength of the green light is

        The stopping potential   is    

At  stopping potential the kinetic is also maximum because this where the electron(causing the current ) would flow at it highest speed before return to zero

   So the maximum  kinetic energy of this electron in term of electron volt is  

This maximum kinetic energy is mathematically represented as

Where h is the planck's constant with a value

            c is the speed of light

            is the work function

Making the subject of the formula

Substituting values

i think the answer is a, hope this : )