A uniform magnetic field of magnitude 0.200 T is directed along the positive x axis. A positron moving at 5.20 106 m/s enters the field along a direction that makes an angle of 85.0° with the x axis. The motion of the particle is expected to be a helix.
2007-03-22 03:54:02 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Physics
I need to find the pitch and the radius of trajectory.... thanks
2007-03-22 04:12:21 · update #1
To work this out we are equating 2 equations.....
The motion of the particle will be a circle (the radius of this path depends on these two equations)
F(L) = Lorentz Force = q (v X B) = q v B sin theta
Motion in a circle = m v^2 / r
We set these equal to each other......
q v B sin theta = m v^2 / r
(1.6 x 10^-19) x (5.20 x 10^6) x 0.2 x sin 85 = (9.11 x 10^-31) x (5.20 x 10^6)^2 / r
1.6577 x 10^-13 = 2.463344 x 10^-17 / r
r = 2.463344 x 10^-17 / 1.6577 x 10^-13
radius = 1.486 x 10^-4 metres
The positron will move in a circle of radius 1.486 x 10^-4 metres.
2007-03-22 04:14:51 · answer #1 · answered by Doctor Q 6 · 0⤊ 0⤋
Where everything except q is a vector, the force is F, V is velocity, B is the field --
F = q V X B where X is the curl.
2007-03-22 11:03:55 · answer #2 · answered by Gene 7 · 0⤊ 0⤋
I can't find a question in there!
2007-03-22 11:00:30 · answer #3 · answered by Anonymous · 0⤊ 0⤋