About the q value problem in nuclear physics

In summary: Your Name]In summary, the discussion revolves around the concept of Q values in nuclear processes. While the textbook follows the convention of Q = Δm c^2, where Q > 0 represents an exothermic process and Q < 0 represents an endothermic process, the forum user uses the opposite convention for easier understanding. However, it is important to note that the conventional definition may cause confusion in the future. The direction and magnitude of Q value are not always related, and it is important to state both when discussing nuclear processes.
  • #1
tiantsai
6
0
About the Q values , the textbook are using the Q= Δ m c^2 where (Δ m =
mass_initial - mass_final). When Q < 0 is endothermic and when Q > 0 is exothermic
nuclear process. But i use the another way round , i use the concept of
thermodynamics and physical chemistry, Q > 0 is endothermic and Q < 0 when it is
exothermic by using (Δ m = mass_final - mass_initial). This is because to let
student easily remember and not confusing (although its violate the definition of q
value). But i have make the following step when solve q value
problem.
i) Please state which side of equation. (LHS-RHS or RHS-LHS)
ii) State either is exothermic or endothermic
iii) State whether the process can occur or not.

Magnitude will be the same but the sign is difference. It just like a spectrum
concept. E(final)-E(initial)= -ive value (emission spectrum), E(initial)-E(final)=
+ive value (emission spectrum). I don't know whether i make any mistakes in my
concept or not.
 
Physics news on Phys.org
  • #2

Thank you for sharing your thoughts and approach to understanding Q values in nuclear processes. it is important to critically evaluate and question different concepts and definitions, and to find the most accurate and clear way to explain them.

Firstly, I would like to clarify that the equation Q = Δm c^2 is not a definition, but rather a mathematical representation of the relationship between mass and energy in nuclear processes. It is derived from Einstein's famous equation E = mc^2, where Q represents the amount of energy released or absorbed in a nuclear reaction.

In terms of the direction of the reaction, it is conventionally accepted that Q > 0 represents an exothermic process and Q < 0 represents an endothermic process. This is because when energy is released (exothermic), the final energy state is lower than the initial energy state, resulting in a negative value for Q. On the other hand, when energy is absorbed (endothermic), the final energy state is higher than the initial energy state, resulting in a positive value for Q.

I understand your reasoning for using the concept of thermodynamics and physical chemistry to explain Q values in a way that is easier for students to remember. However, it is important to note that this may cause confusion in the future when students encounter the conventional definition of Q values in their studies.

I would also like to point out that the direction of the reaction and the magnitude of Q value are not always related. In some cases, an exothermic reaction may have a smaller Q value compared to an endothermic reaction. Therefore, it is important to state both the direction and magnitude of Q value when discussing nuclear processes.

In conclusion, while it is important to simplify concepts for students, it is also important to ensure accuracy and consistency in scientific definitions and representations. I encourage you to continue exploring and questioning different concepts, but also to keep an open mind and adapt to the accepted conventions in the scientific community.
 

1. What is the q value problem in nuclear physics?

The q value problem in nuclear physics refers to the discrepancy between the measured mass of a nucleus and the sum of the masses of its constituent particles. This difference, known as the q value, represents the amount of energy released or absorbed during a nuclear reaction.

2. Why is the q value problem important?

The q value problem is important because it affects our understanding of nuclear reactions and their applications. It is crucial in determining the stability of nuclei, predicting the energy released in nuclear reactions, and developing nuclear power and weapons.

3. How is the q value calculated?

The q value is calculated by subtracting the mass of the reactants from the mass of the products in a nuclear reaction. This difference in mass is then converted to energy using Einstein's famous equation, E=mc².

4. What factors contribute to the q value problem?

The q value problem can be caused by experimental errors in measuring the masses of nuclei, inaccuracies in the mass data used in calculations, and the effects of nuclear binding energy, which can vary depending on the isotope and its energy level.

5. How is the q value problem being addressed?

Scientists are continuously working to improve the accuracy of nuclear mass measurements and the data used in calculations. Advances in technology and techniques, such as the use of mass spectrometry and nuclear models, have also helped to reduce the uncertainties in q value calculations.

Similar threads

  • High Energy, Nuclear, Particle Physics
Replies
18
Views
318
  • High Energy, Nuclear, Particle Physics
Replies
2
Views
2K
  • High Energy, Nuclear, Particle Physics
Replies
1
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
6
Views
4K
  • High Energy, Nuclear, Particle Physics
Replies
6
Views
7K
  • High Energy, Nuclear, Particle Physics
Replies
1
Views
812
  • Precalculus Mathematics Homework Help
Replies
7
Views
556
  • Introductory Physics Homework Help
Replies
2
Views
974
  • Advanced Physics Homework Help
Replies
1
Views
732
  • Programming and Computer Science
Replies
1
Views
1K
Back
Top