Photoelectric Effect - Laboration

[Gunnar9711]

Homework Statement

"During a laboratory experiment with photoelectric effect, a metal plate is irradiated with light. The voltage that completely stops the beam of electrons is then measured.

When the wavelength is 546 nm, the voltage is 0,38 V. When the wavelength is 410 nm, the voltage is 1,13 V.

Calculate an experimental value for Planck's constant and the work function of the metal plate."

Homework Equations

$E_{F} = E_{K} + E_{0} \\<br /> E_{F} = \frac{hc}{\lambda} \\<br /> U = \frac{E}{Q} \\$

The Attempt at a Solution

What I am wondering is, have I solved the problem correctly? I know many would address the problem by making a graph with the kinetic energy on the y-axis and the frequency on the x-axis... Thus I am not sure if my way works, however I believe it should...
So: Is my solution correct?

 

[mfb]

You have two equations and two unknowns. This gives exactly one value for the Planck constant, not two - the difference you see comes from your rounding errors.
Drawing it would give the same result, but solving the equations on paper is better.