What is the dimensional formula for Planck's constant?

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Discussion Overview

The discussion centers around the dimensional formula for Planck's constant, exploring various perspectives on how to derive or understand it. Participants engage in a mix of technical reasoning and personal experiences related to learning physics.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Homework-related

Main Points Raised

  • One participant seeks the dimensional formula for Planck's constant, expressing uncertainty about the correct representation.
  • Another suggests using the uncertainty principle as a mnemonic for remembering the dimensions of Planck's constant.
  • A participant proposes the dimensional formula as h = m L² T⁻¹, but acknowledges the potential for error in assumptions.
  • It is noted that the Wikipedia page does not explicitly provide the dimensional formula, leading to confusion among participants.
  • One participant confirms that the dimensional formula can be derived from the relationship [h] = [E][t] = Js, and further explains that Js = kg m²/s, aligning with the earlier assumption.
  • There are expressions of frustration regarding the teaching approach, with some participants feeling that hints and guidance complicate rather than clarify the issue.
  • Another participant emphasizes the importance of understanding the process of arriving at answers in physics, rather than just obtaining answers.

Areas of Agreement / Disagreement

Participants express differing views on the appropriateness of teaching methods and the clarity of the information available on the topic. There is no consensus on the best approach to answering the original question, and the discussion remains unresolved regarding the most effective way to convey understanding.

Contextual Notes

Some participants express uncertainty about the definitions and relationships involved in deriving the dimensional formula, indicating a reliance on external sources that may not provide clear or consistent information.

forest chump
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Good day. Forum newbie / physics rookie here.

I need the dimensional formula for Planck

5p3ll!ng is not my strong suite...but I can quantify "5p3ll!ng" to the nth degree.
 
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Sorry, cell phone typo...

The dimensional formula for Planck's Constant... m? L? T?
 
What about using wikipedia?

A good way to remember the dimension of h is the uncertainty principle. xp, Et, lθ, etc. all have the same dimension as h.
 
Thanks kith...

Have you looked at the Wikipedia page for the Planck Constant and found the dimensional formula? It's not there.

Also, google produces inconsistent responses.

I'm assuming h = m L^2 T^-1

However, assumptions will land me in algebraic purgatory. I'll review your response to verify my assumption...
 
forest chump said:
Have you looked at the Wikipedia page for the Planck Constant and found the dimensional formula? It's not there.
Yes it is. It says "Js" numerous times. You could have arrived there also by considering my hint [h]=[E][t]=Js. Also Js = kg m² / s, so your assumption is correct.
 
kith: I asked a simple straight-forward question that has a difinitive answer. You gave me homework. I even said "physics rookie".

You can lead a horse to water, but you can't make a physics rookie drink mass, length, and the reciprocal of time by offering hints that the uncertainty principal has ANYTHING to do with joules multiplied by time.

That's for future reference.

Thanks for confirming my assumption...I'm going to take your lesson to heart so I can move on from my rookie status. :)
 
I was trying to understand what prevented you from solving the simple question by using wikipedia. Physics is not so much about answers but about how you get there. Sorry for assuming that you wanted to understand. ;-)

forest chump said:
You can lead a horse to water, but you can't make a physics rookie drink mass, length, and the reciprocal of time by offering hints that the uncertainty principal has ANYTHING to do with joules multiplied by time.
Why not just ask about the hint if you don't understand it? The uncertainty principle for energy and time reads ΔEΔt ≥ ħ/2. The right-hand side has the dimension of h, so the left-hand side needs to have the same dimension as h. This tells you that the dimension of h is Js.
 
Why not ask about the hint?

Because math & physics gurus are notoriusly "holier than thou". Asking about hints often leads me to long-winded discusions and complex formulas that confuse the issue even futher.

That's why I prefer industrial arts. :)
 
forest chump said:
kith: I asked a simple straight-forward question that has a difinitive answer. You gave me homework.

Around here we tend to take seriously the parable about giving a man a fish versus teaching him how to fish. :wink:
 
  • #10
jtbell: when dealing with a rookie fisherman, do you hand him a shovel and expect he should know that it's used to dig for worms?

Teaching a rookie means walking him through the process.

Again: "holier than thou".
 
  • #11
The question has been asked and answered, and has derailed. Closed.
 

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