help please, motion of charged particle in mag field

ballahboy

A proton moves in a circular orbit perpendicular to a uniform magnetic field of 0.758T. Find the time it takes the proton to make one pass around the orbit.

Just need someone to help me start off. All I have is that the B=0.758T, q=1.6x10^-19C and m=1.67x10^-27kg. What formulas do I need to use to find t?
Thanks

dextercioby

U can prove (i advice u to do it) that

[tex] r=\frac{mv}{qB} [/tex]

Exploit the connection beteen T,v & r.

Daniel.

ballahboy

hmm so r=mv/qB is derived from mv^2/r=qvB. I got r=(1.4x10^-8)v. the thing is.. i dont kno the relationship between the time, radius and velocity. Do i use r to find the circumference and multiply that by the velocity? im not really sure..
thanks for the response

dextercioby

Yes,that "v" is the constant tangential speed.Multiplied with the period should give exactly 2\pi r...

Daniel.

ballahboy

ok i got the correct answer now.. THanks a lot!! :D