DeBroglie wavelength, kE to (p) conversion?

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SUMMARY

The discussion centers on calculating the de Broglie wavelength from kinetic energy (kE) when mass and velocity are unknown. It is established that both the rest mass and velocity are essential to determine kE for a relativistic particle. Alternatively, total energy and rest mass can be used to find momentum (p). Approximations may apply if the particle's speed is known to be non-relativistic or relativistic, but clarity on the known parameters is crucial for accurate calculations.

PREREQUISITES
  • Understanding of de Broglie wavelength concepts
  • Knowledge of kinetic energy and momentum relationships
  • Familiarity with relativistic and non-relativistic physics
  • Basic grasp of total energy equations in physics
NEXT STEPS
  • Study the relationship between kinetic energy and momentum in both relativistic and non-relativistic contexts
  • Learn how to calculate de Broglie wavelength using known mass and velocity
  • Explore total energy equations for relativistic particles
  • Investigate approximations for calculating momentum at varying speeds
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Students and professionals in physics, particularly those focused on quantum mechanics and particle physics, will benefit from this discussion.

Joel DB
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I have a relatively simple question. I should know this, but...
I need to solve for the deBroglie wavelength when only the kinetic energy is known. Shouldn't I be able to convert kE to momentum (p), when the object does not have a known velocity or mass...?

Much thanks...
JD
 
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Joel DB said:
I have a relatively simple question. I should know this, but...
I need to solve for the deBroglie wavelength when only the kinetic energy is known. Shouldn't I be able to convert kE to momentum (p), when the object does not have a known velocity or mass...?

Much thanks...
JD
No. You need both the rest mass and the velocity to determine the kinetic energy of a relativistic particle. Alternatively, you can use the total energy and the rest mass to determine the momentum (essentially the same thing).

However, if you know that the particle is moving at non-relativistic speeds, or very close to the speed of light, then there are some approximations you can use. But again, the usefulness of these depends on what you know.

Perhaps it would be easier if you tell use precisely what you know.
 

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