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### Delta x

Posted: **Sun Oct 04, 2015 11:12 pm**

by **Angela Chen**

What exactly does delta x in Heisenberg's indeterminacy equation stand for? Does delta x stand for different things (eg. diameter, momentum, percentage of another value, etc.) in different situations? If so, what are some of the possible situations? How do we know which given value in a question is delta x, and how do we know if the question is asking for delta x?

### Re: Delta x

Posted: **Sun Oct 04, 2015 11:30 pm**

by **Delaire F**

x refers to the position of the entity

delta x is the uncertainty or indeterminacy of the position of that entity in an environment.

(p and delta p refer to momentum.)

The second example in the workbook regarding Heisenberg's indeterminacy equation refers to an electron orbiting an atom. We know, through experimentation, that the electron exists somewhere within the atoms atomic diameter (in the electron cloud), however we cannot accurately state the momentum and position of the electron at any one given moment.

The delta x is used to describe the possible space (indeterminacy) where the electron exists at a given moment.

You'll know when you're given delta x because there will be a reference to space or location ("For H-atom the electron is confined to its atomic diameter of 2.5 x 10^-10 m").

### Re: Delta x

Posted: **Tue Oct 13, 2015 9:36 pm**

by **Jordanmjones13**

If they give us delta x as a radius, do we have to multiply it by 2 to make it the diameter or do we use whatever they give us?

### Re: Delta x

Posted: **Tue Oct 13, 2015 11:18 pm**

by **Wesley Shen Lec 4**

Delta x just refers to the uncertainty in position. If you are given the radius, you don't necessarily need to multiply by 2, you just take it how the problem is posed. If we are given that an electron is confined within the nucleus, then it's delta x would be the diameter of the nucleus, for it could be anywhere within the nucleus. If it's confined within the radius, then you would use the radius.

### Re: Delta x

Posted: **Wed Dec 02, 2015 6:38 pm**

by **704628249**

Delta x is the uncertainty in position. So if they say that an electron is in its nuclear diameter, the diameter would be your uncertainty in position because it could be anywhere in this location. Or if they say that the location is 2.0m +/- 1, your uncertainty would be 2 because it could be between 3 or 1.