Bohr model

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1. Aug 29, 2016

gruba

1. The problem statement, all variables and given/known data
On which orbit of hydrogen atom an electron has the speed of $734 km/s$?

2. Relevant equations
Bohr's second postulate: $mvr=nh,m=9.109\cdot 10^{-31}kg,v=734 km/s,h=6.626\cdot 10^{-34} m^{2}kg/s$

3. The attempt at a solution
By using the second Bohr's postulate, we get $$6686.006\cdot 10^{-28}r=6.626\cdot 10^{-34}n$$

Question: What is the value of radius of orbit of electron, $r$?

If we set that $r=0.0529 nm$, then we get $n=0.053$ and $n$ should be positive integer.

2. Aug 29, 2016

Staff: Mentor

That value is for the first Bohr orbit, $n=1$. For $n > 1$, the radius is bigger. You need another equation relating $r$ to $n$ or $r$ to $v$.

3. Aug 29, 2016

gruba

What is that equation?

4. Aug 29, 2016

Staff: Mentor

You can use the equation that balances the centripetal force and the Coulomb force. Don't you have that equation in your notes/textbook?