Nuclear and Particle Physics Nuclear and Particle Physics Help Forum Sep 24th 2009, 09:19 AM #1 Banned   Join Date: Jul 2009 Posts: 66 help genii 1.According to Bohr model, magnetic field at the centre (at the nucleus) of a hydrogen atom due to the motion of electron in nth orbit is proportional to which given option (A) 1/n3 (B) 1/n5 (C) n5 (D) n3 plz explain also. i dont know to solve it.. I wonder magnetic field means intensity or its momenton or strength.. Despite these also i have no idea.   Sep 25th 2009, 11:22 PM #2 Physics Team   Join Date: Feb 2009 Posts: 1,425 This is an interesting question. Think of the Hydrogen atom with the nucleus at the centre. Think of the orbit as a circular wire around it. The Bohr quantization condition gives us the angular momentum L $\displaystyle L\ =\ m\ \omega\ r^2\ =\ \frac{n\ h}{2\ \pi}$ . Thus it can be seen that omega is proportional to n . But $\displaystyle \omega\ =\ 2\ \pi \ f$ where f is the frequency. So f is proportional to n Thus, if we look at any point on the "orbit wire" , it is as though f electrons pass it each sec ( actually it is the same one !) Thus a charge of f . e coulombs passes any point on the wire per sec. e here is the charge of the electron. This corresponds to a current of $\displaystyle I\ =\ \frac{f\ e}{1}$ . Thus I is also proportional to n. Now look up the formula for the magnetic field at the centre of a current carrying loop and find what power of I it corresponds to. It should be the same for n.  Tags genii Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post binayakafle Nuclear and Particle Physics 3 Nov 20th 2009 08:59 PM