Calculate Binding Energy

  • Thread starter deezer
  • Start date
  • #1
18
0

Homework Statement



Calculate the binding energy per nucleon for 4He. Mass is 4.0026u


Homework Equations



E=Δmc^2

The Attempt at a Solution



This is my plan of attack,
first find the Δm.
Mnucleon-Mnucleus [Are these terms right? Nucleon - Nucleus ?]
Δm=4.0026u-(2p+2n)=-0.02928u

E=Δmc^2
=-2.6352x10^15J/nucleus

But the question asked for J/nucleon and I'm not sure what to do now. The correct answer is -1.13x10^-12J/nucleon.
 

Answers and Replies

  • #2
ehild
Homework Helper
15,543
1,909
u is the atomic mass unit, convert it to kg-s.

ehild
 
  • #3
1,506
18
Nucleons are the particles in a nucleus. That is the protons and neutrons
 
  • #4
18
0
So what do I need to change? Isn't nucleon the nucleus, since the nucleus=protons+neutrons.
 
  • #5
1,506
18
A He nucleus contains 2 protons and 2 neutrons. Your calculation of Δm is perfectly correct (0.02928u) but you need to convert u into kg. (1u = 1.66x10^-27kg)
Then use that mass in E = mc^2 to calculate the energy equivalent of this mass defect.
This is the energy holding all of the nucleons (protons and neutrons) in the nucleus.
This is called the BINDING ENERGY OF THE NUCLEUS.
Can you see how to get the BINDING ENERGY OF A NUCLEON ????
 
  • #6
18
0
A He nucleus contains 2 protons and 2 neutrons. Your calculation of Δm is perfectly correct (0.02928u) but you need to convert u into kg. (1u = 1.66x10^-27kg)
Then use that mass in E = mc^2 to calculate the energy equivalent of this mass defect.
This is the energy holding all of the nucleons (protons and neutrons) in the nucleus.
This is called the BINDING ENERGY OF THE NUCLEUS.
Can you see how to get the BINDING ENERGY OF A NUCLEON ????
It's the same thing?
 
  • #7
1,506
18
No... He nucleus contains 4 nucleons. The binding energy PER NUCLEON is the binding energy of the NUCLEUS/4.
It is a way of giving an 'average' binding energy of NUCLEONS and makes analysing Binding energy of all of the NUCLEI easier.
You have got the idea.
The Binding energy PER NUCLEON = Binding energy of NUCLEUS/Number of nucleons
 

Related Threads on Calculate Binding Energy

Replies
3
Views
2K
Replies
2
Views
6K
  • Last Post
Replies
5
Views
650
  • Last Post
Replies
1
Views
772
  • Last Post
Replies
11
Views
3K
  • Last Post
Replies
5
Views
2K
  • Last Post
Replies
4
Views
1K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
0
Views
1K
  • Last Post
Replies
2
Views
3K
Top