## Quanta & Photons

$c=\lambda v$

juleschang16
Posts: 55
Joined: Fri Sep 28, 2018 12:19 am

### Quanta & Photons

Can someone explain the key concept of "equations in quantum mechanics have variables that are quantized or discrete". What is the difference between quantized and discrete?

Becky Belisle 1A
Posts: 81
Joined: Fri Sep 28, 2018 12:18 am

### Re: Quanta & Photons

I think when it says "quantized or discrete" that discrete is just serving as a definition or qualifier for the word quantized. The difference between them is not the main point. When values are quantized they become discrete.

Laura Gong 3H
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Joined: Fri Sep 28, 2018 12:26 am
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### Re: Quanta & Photons

Quantized and discrete are intended to have the same definition here. It just means that the variables in a system has a only a number of distinct values it can be. For example, when we talk about principle energy levels, n, n can only equal to 1, 2, 3 or 4--never 1.2 or 2.4234, etc.

Dimitri Speron 1C
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### Re: Quanta & Photons

It is meant to draw notice to the fact that numbers in quantum equations cannot be "anything" like in a lot of classical mechanics situations. In lecture he used the example F= ma can have pretty much any number for each of those values, whereas in a quantum equation some variables will only be able to have specific values. (like 1,2,3,4...)

Andrew Lam 3B
Posts: 30
Joined: Fri Sep 28, 2018 12:24 am

### Re: Quanta & Photons

In essence, you can never have light that strikes in 1.2 photons, 5.64 photons, etc. The particle nature of light only travels in whole number of "packets".

Nathan Tran 4K
Posts: 92
Joined: Fri Sep 28, 2018 12:16 am

### Re: Quanta & Photons

Doctor Lavelle used a very pertinent example of a water faucet in his discussion of the difference between discrete and quanta variables. Essentially, the holistic view of water exiting a water faucet is comparable to a discrete value because water is seen as continuously flowing. An example of this would be water traveling at a rate of 10 gallons per minute for 10 minutes; the rate is continuous. At a certain point, there were 5.4982097 gallons of water assuming the tub holding the water started at 0 gallons. However, if we scrutinize water on a molecular level, we see that water is really just comprised of water molecules. Water travels one water molecule at a time with no values in between because this would physically be impossible. This is comparable to a quanta variable. A helpful hint is that quanta means "quantity" and quantity should evoke a sense of whole numbers.