## Sapling Wk 2+3 #7

(Wien's law: $T\lambda _{max}=\frac{1}{5}C_{2}$ )

Kaley Qin 1F
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Joined: Wed Sep 30, 2020 9:54 pm

### Sapling Wk 2+3 #7

For question 7, it asks about temperature and wavelength. Does this mean we have to use wein's equation which is mentioned in the textbook or is there some other way to do the problem?

tamara masri_3D
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### Re: Sapling Wk 2+3 #7

Hello! Since the temp is constant, you don't need to worry about it. Therefore, you can use the equation ⋋=h/mv (where v=velocity)

Katie Phan 1K
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### Re: Sapling Wk 2+3 #7

to find the mass, divide the molar mass of O2 by Avogadro's number and then convert it to kg!

Andre Fabian 1F
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### Re: Sapling Wk 2+3 #7

Hi there!

You'd use the deBroglie relation (λ = h/mv) in order to solve this problem.

"h" is Placke's constant, which is 6.626 x 10^-34 J.s^-1.

"m" is the mass of an individual nitrogen dioxide molecule (because nitrogen is only found in nature as a pair), which you can calculate by dividing the molar mass of n2 (28.02) by Avogadro's constant (6.022 x 10^23) to get 4.65 x 10^-23 g. You would need to convert this into kilograms, because Joules contain kg.

"v" is given in the problem: 515.2 m.s^-1

You'd substitute everything in the equation, and you should get 2.77 x 10^-14.

Hope this helps!