Calculating Angular as a Function of Proton Movement in Magnetic Field

AI Thread Summary
The discussion focuses on deriving a formula for protons moving in a magnetic field, specifically looking to express momentum (p) as a function of magnetic field strength (B) and radius (r). The initial formula presented is p = qrB, where q is the charge of the proton. The user seeks clarification on the correct units for B and q to ensure accurate calculations, emphasizing the importance of converting GeV to Joules and using SI units. They provide a revised formula that relates momentum in GeV/c to the magnetic field and radius, concluding with a practical example of a 1 GeV particle in a 3T field. The conversation highlights the complexities of unit conversion and the relationships between physical quantities in magnetic fields.
liquidFuzz
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I just derived a little formula of protons moving in a magnetic field. With the symetry etc I have I get this:

p = qrB

Now I want to calculate the angular as a function like this:

p = constant * B

Where p is Gev/C, r is in meters.

I don't know what numbers or better what form B and q should have to get all numbers right. Anyone care to shine some light on this..?

Edit, my field is 1.74T r in meters.
 
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Rule of thumb for such cases - if you are confused by units, convert everything to SI.
You need to convert GeV into Joules, and express proton charge in Coulombs and speed of light in m/s. Google for those values!
 
Mhmm...

Something like this?

\displaystyle p = 1.602 * 10^{-19} * 5.609*10^{35} r * 1.74 =1.56*r \frac{eV}{c^2} \frac{m}{s}

Edit, I see that I've confused more than the units. I wanted to compute it like this p = constant * r
 
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OK, I see I must do it for you...
p_{[{\rm kg\,m\,s^{-1}}]} = q_{[{\rm Q}]}r_{[{\rm m}]}B_{[{\rm T}]}<br /> = 1.602\cdot 10^{-19}{\rm C}\,r_{[{\rm m}]}B_{[{\rm T}]}
p_{[{\rm GeV}/c]} = \frac{p_{[{\rm kg\,m\,s^{-1}}]}\cdot 3\cdot 10^8{\rm m\,s^{-1}}}<br /> {1.602\cdot 10^{-10}{\rm kg\,m^2\,s^{-2}\,GeV^{-1}}} =<br /> \frac{1.602\cdot 10^{-19}{\rm C}\,r_{[{\rm m}]}B_{[{\rm T}]} \cdot 3\cdot 10^8{\rm m\,s^{-1}}}<br /> {1.602\cdot 10^{-10}{\rm kg\,m^2\,s^{-2}\,GeV^{-1}}} = <br /> 0.3\, \frac{{\rm GeV}}{c}{\rm\,\,m^{-1}\,T^{-1}}\cdot r \cdot B<br />

Or - in other words - easier to remember and imagine - 1GeV particle makes circles of 1m radius in 3T field.
 
Thanks for taking the time to help me!
 
So I know that electrons are fundamental, there's no 'material' that makes them up, it's like talking about a colour itself rather than a car or a flower. Now protons and neutrons and quarks and whatever other stuff is there fundamentally, I want someone to kind of teach me these, I have a lot of questions that books might not give the answer in the way I understand. Thanks
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