## Formula confusion

sarahtang4B
Posts: 132
Joined: Fri Sep 28, 2018 12:27 am

### Formula confusion

Why are the two "h" variables different in the wavelength=hp formula and the Heisenberg equation. In the wavelength equation, I saw on the homework it's plancks constant but for the uncertainty equation it's 1.054e-34. Where does that number come from and why are the two h variables different?

Hanlin Zhu 4G
Posts: 30
Joined: Fri Sep 28, 2018 12:28 am

### Re: Formula confusion

They are different but related. In the Heisenberg equation, the constant you mentioned that has the value 1.05457 x 10^-34 is actually not h. It is "h bar", which means h/2pi.

sarahtang4B
Posts: 132
Joined: Fri Sep 28, 2018 12:27 am

### Re: Formula confusion

Will the constant be given on tests?

Gary Qiao 1D
Posts: 66
Joined: Fri Sep 28, 2018 12:26 am

### Re: Formula confusion

The h in the heisenberg equation actually has a slash through the h, which symbolizes h/2π. This means that the "h" variable, the planck constant, 6.63 x 10^-34 Js is the same in both the wavelength = hp and heisenberg equation.

Gary Qiao 1D
Posts: 66
Joined: Fri Sep 28, 2018 12:26 am

### Re: Formula confusion

The h constant would be given on the test

anishathomas
Posts: 35
Joined: Fri Sep 28, 2018 12:25 am

### Re: Formula confusion

I used h as the same value for both questions-and it worked. Just make sure you use h/4pi instead of h/2pi instead of the different value of h.