Problem with units? (trying to solve a normalized function)

  • Thread starter Thread starter Labboi
  • Start date Start date
  • Tags Tags
    Function Units
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
9 replies · 2K views
Labboi
Messages
5
Reaction score
0
Homework Statement
I'm trying to solve a normalized function and cannot seem to get the right answer.
Relevant Equations
Kappa=sqrt(2m(EB)/hbar^2))
-kappa*R=-0.34
I'm trying to solve for this in a deuteron problem. But can't seem to get the right answer.
The reduced mass of the deuteron is 469.4 MeV, the binding energy Eb is 2.226 MeV and R = 1.5fm.

Using hbar = 6.5817x10^-16 eV.s

I get Kappa = sqrt((2(469.4)*2.226)/(6.5817*10^-22)^2) = 6.94*10^16

-kappa*(1.5*10^-13) = 10418.

I feel like I'm messing up units or something.
 
Physics news on Phys.org
fm=1.0 E-15 m, but your arithmetic has other errors as well. Google of the mass of the deuteron also is in disagreement.
 
Labboi said:
I feel like I'm messing up units or something.
Like not including them on your answer? Have you tried including the units and working out the end result?
 
Charles Link said:
fm=1.0 E-15 m
I disagree. One fm is ##10^{-6}~\rm nm##.
 
vela said:
I disagree. One fm is ##10^{-6}~\rm nm##.
Then, in fact, you agree with @Charles Link!
 
  • Like
  • Haha
Likes   Reactions: berkeman, vela and Charles Link
Kappa = Sqrt((2(469.4MeV/3.0*10^8m.s^-2)*2.226Mev)/(6.5817*10^-22MeV.s)^2 = 5939.86

-Kappa*R = 5939.86*1.5*10^-13 = 8.90*10^-13

I'm trying to convert the fm into cm
 
You need to take ##c ## to the second power. In addition ## \hbar ## is to the second power inside the square root. You need to do the arithmetic carefully.
 
  • Like
Likes   Reactions: Labboi
I did, just forgot it in the equation, sorry.
 
Thank you, I must have messed up my parentheses, it's been a long night.