Barrier Tunneling and Kinetic Energy

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SUMMARY

The discussion focuses on calculating the kinetic energy of a proton during barrier tunneling and reflection. The transmission coefficient (T) is calculated using the formula T = e^-2bL, where L is the barrier length (10 fm) and b is derived from the potential barrier height (10 MeV) and proton energy (3 MeV). The calculated transmission coefficient is T = e^-11.617, approximately 9.011 x 10^-6. It is established that the kinetic energy remains unchanged in both tunneling and reflection scenarios due to the conservation of energy principle.

PREREQUISITES
  • Understanding of quantum mechanics concepts, specifically barrier tunneling.
  • Familiarity with the transmission coefficient formula T = e^-2bL.
  • Knowledge of kinetic energy calculations in quantum systems.
  • Basic grasp of potential energy and conservation of energy principles.
NEXT STEPS
  • Study the derivation and implications of the transmission coefficient in quantum mechanics.
  • Explore the concept of potential barriers in quantum tunneling.
  • Learn about the relationship between kinetic energy and potential energy in quantum systems.
  • Investigate the applications of barrier tunneling in modern physics and technology.
USEFUL FOR

Students of physics, particularly those studying quantum mechanics, as well as educators and researchers interested in barrier tunneling phenomena and energy conservation principles.

nickm4
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1. Homework Statement


b). Find the kinetic energy K (sub t), the proton will have on the other side of the barrier if it tunnels through the barrier.

c) Find the kinetic energy K (sub r), it will have if it reflects from the barrier.

Variables:

Transmission Coefficient (T)

T= e^-2bL
T was found to be T= e^-11.617 or (9.011*10^-6)
e= 2.718...
L= length of the barrier which is given as 10fm or (10.0*10^-15m)

b= sqrt(((8pie^2)(m)(U(sub b)-E))/(h^2))

m= mass of proton(1.673*10^-27kg)
Ub= height of the potential barrier(given= 10MeV)
E= energy of the proton (given= 3MeV)
h= plank's constant (6.62*10^-34)

2.

Homework Equations



T= e^-2bL
b= sqrt(((8pie^2)(m)(U(sub b)-E))/(h^2))

The Attempt at a Solution



I solved the first part of the question to find the transmission coefficient, T. But I'm not sure how Kinetic energy is related. Other than through b.

This question is taken from " Fundementals of Physics" Halliday/Resnick 7th ED. Question: 38-63

Thanks Tons.
 
Physics news on Phys.org
In both cases (reflection and tunneling) the energy remains unchanged. By conservation of energy the energy cannot change because it is not going anywhere. This holds for electrons and other particles as well.
 

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