Find the radius of each circular path

[Canuck269]

Homework Statement

Determine the path of an electron if the electron was shot at 2.5 x 10^5 m/s diagonally into a magnetic field. Find the radius of each circular path.

The angle is 30 degrees.I think that if the velocity and field are in same direction there is no force...i think. So that means you only want the component perpendicular to the field. Which is 1.25 x 10^5 m/s

I just don't understand how you can find the radius if you are given no info about the magnetic field. F= qvB and F= m v^2/r So I tried putting that together but I still have 2 variables...

The question was listed as challenger :P So I don't think it's missing info.

 

[mjsd]

you need info about the B-field or some other observations about the path of the electron.

 

[ogb p]

I would suggest using the equations you mentioned, F=qvB and F=mv^2/r, to solve for the radius of the circular path. The missing variable, magnetic field (B), can be found by using the angle given (30 degrees) and the fact that the force is perpendicular to both the velocity and the field. This can be done by using the trigonometric identity: sinθ = F/qvB. Once the magnetic field is determined, the radius can be calculated using the second equation: r=mv/sqrt(qB). Alternatively, you can also use the equation r=mv/sqrt(mF) since the mass of the electron is known. I hope this helps.