Question

I'm looking for the Planck's constant using the data I gathered for the potential difference and frequency. Then, I drew a best fit line and find its slope. My problem is, I have to find uncertainty but I don't have any idea if I will include it in the final answer for the Planck's constant? Also, how can I find the percentage error with the uncertainty?

Answer 1

I'm lazily looking up things to see if a mental bell is rung...

Otherwise, I can show you what I was taught. But I don't understand it too well and I'm not sure if this is the correct application. So it might be a bad idea to bring it up...

Answer 2

just tell me maybe i can get some ideas :)

Answer 3

Oh! I found this:
http://spiff.rit.edu/classes/phys273/uncert/uncert.html
I don't know if it's helpful yet, but there's a section on uncertainty of a graph! Just scroll down to it!

Answer 4

Did you use Microsoft Excel?

Answer 5

I'm also following that site (I'm doing the graph manually by hand -.-)

and yes I used Microsoft excel. It already gave me the uncertainty but I'm not sure how to use it to find the planck's constant and the percent error

Answer 6

Is the Plank's constant \(\dfrac{\Delta V}{\Delta f}\)? Then it's value is the slope of the line, and the uncertainty is the uncertainty in the slope.

Look into Excel's "LINEST" feature. It's a line estimation tool.

Answer 7

I think you have to highlight a 3 by 2 box, put in the parameters (like LINEST(...) ), and hold down shift and press enter..

Answer 8

I think you might only need a 2 by 2 box

Answer 9

actually, 2 by 1....

Answer 10

Planck's constant is \(\Large h=\frac{e \Delta V}{f}\)

okay i'll try that, give me a sec

Answer 11

Oh, okay.

So, it's not the change in frequency? Is Plank's constant supposed to be the slope, then? I suppose you know!

I have to go. Take care! :)

Answer 12

yes it is the slope if the graph is Energy vs. Frequency (from what i know but i'm not sure)

thanks for the help!