What are the units for the Heisenberg Uncertainty Principle?

In summary, energy levels can fluctuate by some amount, for a short time, t. As long as e x t does not exceed h/4pi, the units for time and energy are correct.
  • #1
Lunct
133
16
To my understanding(correct me if I am wrong), one consequence of the Heisenberg Uncertainty Principle is that energy levels can fluctuate by some amount, e, for a short time, t. As long as e x t does not exceed h/4pi (where h= Planck's constant). My quarry is that what are the units for the time and energy. I assume it is in joules and seconds but the book did not specify so I am unsure.

P.S this energy fluctuation is so weird, it kinda disproved the law of the conservation of energy.
 
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  • #2
you assumed correct ...
 
  • #3
Ssnow said:
you assumed correct ...
thanks for clarifying
 
  • #4
Lunct said:
I assume it is in joules and seconds but the book did not specify so I am unsure.
When you look up the value of Planck's constant, you will see that it is stated with some units: For example, the first Google hit says that ##h=6.62607004\times{10}^{-34} m^2 kg / s##. So if you are measuring your distances in meters, your masses in kilograms, and your times in seconds that's the numerical value of Planck's constant that you'd plug into the calculation. When you do, you'll find that your answer for the energy comes out in units of ##kg\cdot{m}^2/s^2##, the unit that we call a Joule. So yes, Joules are right, but that's not something you have to assume - you chose to have the answer come out in Joules when you chose to write Planck's constant in that form.
P.S this energy fluctuation is so weird, it kinda disproved the law of the conservation of energy.
It does not, but with quantum mechanics you do have to be much more careful and mathematically precise in the way that you state and use the law. We have many other threads on this topic, but if you can't find one that explains it to your satisfaction, feel free to start a new thread asking that question.
 
  • #5
Nugatory said:
When you look up the value of Planck's constant, you will see that it is stated with some units: For example, the first Google hit says that ##h=6.62607004\times{10}^{-34} m^2 kg / s##. So if you are measuring your distances in meters, your masses in kilograms, and your times in seconds that's the numerical value of Planck's constant that you'd plug into the calculation. When you do, you'll find that your answer for the energy comes out in units of ##kg\cdot{m}^2/s^2##, the unit that we call a Joule. So yes, Joules are right, but that's not something you have to assume - you chose to have the answer come out in Joules when you chose to write Planck's constant in that form.
It does not, but with quantum mechanics you do have to be much more careful and mathematically precise in the way that you state and use the law. We have many other threads on this topic, but if you can't find one that explains it to your satisfaction, feel free to start a new thread asking that question.
Thank you for the reply.
 

Related to What are the units for the Heisenberg Uncertainty Principle?

1. What are the units for the Heisenberg Uncertainty Principle?

The units for the Heisenberg Uncertainty Principle are typically expressed in terms of energy multiplied by time, or in other words, the product of the uncertainty in energy (ΔE) and the uncertainty in time (Δt). This can be written as kg·m²/s, or in more simplified terms, joule seconds (J·s).

2. Can the units for the Heisenberg Uncertainty Principle be converted to other units?

Yes, the units for the Heisenberg Uncertainty Principle can be converted to other units, as long as the resulting units remain consistent with energy multiplied by time. For example, J·s can be converted to electron volts (eV), which is a commonly used unit in quantum mechanics.

3. How does the Heisenberg Uncertainty Principle relate to Planck's constant?

The Heisenberg Uncertainty Principle is directly related to Planck's constant (h). In fact, Planck's constant is a fundamental constant in quantum mechanics and is used to calculate the uncertainty in energy and time in the Heisenberg Uncertainty Principle. The smaller the value of Planck's constant, the smaller the uncertainty in energy and time.

4. Are there any other quantities besides energy and time that are affected by the Heisenberg Uncertainty Principle?

Yes, the Heisenberg Uncertainty Principle can also be applied to other pairs of conjugate variables, such as position and momentum, or angular position and angular momentum. However, the principle is most commonly discussed in terms of energy and time.

5. How does the Heisenberg Uncertainty Principle affect our understanding of the physical world?

The Heisenberg Uncertainty Principle has significant implications for our understanding of the physical world, particularly at the subatomic level. It suggests that it is impossible to simultaneously know the exact position and momentum of a particle, and that there will always be some level of uncertainty in our measurements. This principle also plays a crucial role in quantum mechanics and the development of theories about the behavior of particles at the atomic and subatomic level.

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