Calculating Magnetic Field Magnitude at Fermilab Accelerator in Batavia, IL

[dev-hud]

At the fermilab accelerator in Batavia, Illinois, protons having momentum 4.8 x 10^-16 kg x m/s are held in a circular orbit of radius 1 km by an upward magnetic field. What is the magnitued of this field?


r = 1000 m

So i do not understand what are we trying to find here? the question asks for the magnitude of the field, but how are we to solve for the magnitude with just 2 varibale given to us? Very Confuzed

 

[tiny-tim]

Hi dev-hud!

Do it systematically, one step at a time:

i] what is the force of a field B on the proton?

ii] what force is necessary to make the proton move in a circle of radius r?
​

(call the mass m, and the velocity v)

 

[tcham]

B=mv/qr

since p=mv therefore: B=p/qr