Page **1** of **1**

### h vs. ħ?

Posted: **Thu Oct 29, 2020 7:17 pm**

by **Angel More**

Can you explain the difference between h (6.62607015×10−34) and ħ (h-bar) (1.054571817×10−34) to me please?

And when do we use the 1) formula and the 2) formula?

1) ∆p ∆x ≥ h/4π

2) ∆p ∆x = (1/2) ħ

Thank youuuuu

### Re: h vs. ħ?

Posted: **Thu Oct 29, 2020 7:22 pm**

by **Alexandra Ahlschlager 1L**

I think the h-bar symbol represents h/2pi, so (½)h-bar would be equal to h/4pi. Since both equations are basically equivalent to each other, I’m pretty sure you can use whichever form you’re most comfortable with. Hope this helps!

### Re: h vs. ħ?

Posted: **Thu Oct 29, 2020 7:25 pm**

by **Nathan Lao 2I**

h is Planck's constant, which is defined as 6.626x10^-34 J s. ħ is equivalent to Planck's constant(h)/2pi. I'm assuming the second formula should have a ≥ instead of an = sign but the formulas should represent the same thing, just in different notations.

The textbook also explains this in section 1B.3 The Uncertainty Principle.

### Re: h vs. ħ?

Posted: **Thu Oct 29, 2020 7:42 pm**

by **AustinMcBrideDis3L**

ħ is just some chemistry technical term/jargon for h/2π. Thus when its (1/2)*ħ it equals the h/4π in the other equation. Also the equations should both have a greater than or equal to sign, so I don't know why there is a discrepancy there.

### Re: h vs. ħ?

Posted: **Thu Oct 29, 2020 8:56 pm**

by **Charlie Russell 2L**

ħ is not h/4pi!!! It is h/2pi. 4pi was only in the equation used for the midterm because there was a 2 in the denominator to multiply!

### Re: h vs. ħ?

Posted: **Fri Oct 30, 2020 2:10 pm**

by **Adrienne Yuh 2B**

The h-bar symbol represents 2pi! I would ultimately just follow the formula sheet to keep it a familiar representation of the equation.

### Re: h vs. ħ?

Posted: **Fri Oct 30, 2020 8:59 pm**

by **Aayushi Jani 3A**

h-bar is h/2pi. You can use either equation, but personally, I prefer just remembering h and using ∆p ∆x ≥ h/4π.

### Re: h vs. ħ?

Posted: **Sat Oct 31, 2020 2:19 pm**

by **Jaden Haskins 2E**

Is h-bar used in any other circumstances, or is the indeterminacy equation the only one that uses this?

### Re: h vs. ħ?

Posted: **Sat Oct 31, 2020 2:35 pm**

by **Olivia Monroy 1A**

I prefer using the equation with just h, as that's what Lavelle teaches, but the textbook uses the other just to symbolize h/2pi.. they're the same thing/interchangeable.

### Re: h vs. ħ?

Posted: **Sat Oct 31, 2020 2:41 pm**

by **Bella Bursulaya 3G**

Hi! h is planck's constant, and h bar is a reduced value of h. 1/2h/2pi is the same thing as h/4pi, they equal the same value. The equations should both have a greater than or equal sign, but equal is the most optimistic value. I hope this helps!

### Re: h vs. ħ?

Posted: **Sun Nov 01, 2020 8:19 pm**

by **t_rasul2I**

I understand that h bar is the same set up as h/4pi. But why do we have a complicated/different set up of the equation. Is there something it was derived from?

### Re: h vs. ħ?

Posted: **Sun Nov 01, 2020 11:28 pm**

by **Griffin G**

ħ, or h bar is simply h/2pi. h as you know is plancks constant. h bar exists just to save space. So (1/2)ħ is the same as h/4pi.