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### De Broglie wavelength - when can it be seen

Posted: Sat Oct 13, 2018 3:28 pm
During lecture, Professor Lavelle was saying that any wavelength smaller than 10^-18 cannot be seen. What does it mean for a wavelength to be seen? Thank you!

### Re: De Broglie wavelength - when can it be seen

Posted: Sat Oct 13, 2018 3:31 pm
Hello! Im just commenting because I had the same question, but Im not sure whether or not he said "can be seen" or can be measured as per laboratory measures? For instance one angstrom is 10^-10, so chemists can definitely "measure" that. He might have meant that anything smaller than that is hard or difficult to measure. And 10^-18 is smaller than 10^-10.

### Re: De Broglie wavelength - when can it be seen

Posted: Sat Oct 13, 2018 3:34 pm
Essentially the wavelength cannot be measured when it is smaller than 10^-18 thus it is used as the cut off point

### Re: De Broglie wavelength - when can it be seen

Posted: Sat Oct 13, 2018 3:37 pm
I believe he was reffering to measurable wavelike properties. If the calculated wavelength could be experimentally seen in a lab.

### Re: De Broglie wavelength - when can it be seen

Posted: Sat Oct 13, 2018 3:40 pm
In class he used an example where the wavelength was measured at 1.64 x 10^-38m which is unmeasurable,
However an example with a wavelength of 1.4 x 10^-10m was

### Re: De Broglie wavelength - when can it be seen

Posted: Sat Oct 13, 2018 4:08 pm
I think he was maybe saying that when things have a large enough mass, their wavelengths become so small that they are basically negligible. For example, all things made of matter have wavelike properties, including things like cars. But, you don't see a car squiggling with waves down the road. The same thing goes for things like billiard balls. If you shot billiard balls at a wall with two holes in a similar experiment to the one he showed with light, the billiard balls would only be able to pass through the holes in a line, rather than diffracting in directions not directly in from the hole, as light does.