# Homework Help: Planck Constant Question

1. Aug 11, 2005

### DaltonGR

Hello,

First time at this site really good.

So on to the point.How can i calculate the Planck constant so i can compare it with the already known number for it??its for a physics test and i cant find out ...

2. Aug 11, 2005

### Nylex

You can do this with the photoelectric effect. You know the equation $KE_{max} = hf - \phi$, where $\phi$ is the work function of the metal and $KE_{max}$ is the maximum energy of the emitted electrons. You need to relate that equation to that of a straight line, ie. y = mx + c, then you can calculate a value for h.

3. Aug 11, 2005

### DaltonGR

Because im not that good can you help me more.It will save me

thnx