In: Physics
One electron collides elastically with a second electron initially at rest. After the collision, the radii of their trajectories are 1.00 cm and 2.50cm. The trajectories are perpendicular to a uniform magnetic field of magnitude 0.0380 T. Determine the energy (in keV) of the incident electron.
The magnetic force on electron during the trajectory is
m v 2 / r = B q v
v = B q r / m
here q is charge on electron, r radius of trajectories, and m is mass of electron
The speed of each electron after collision is
and
kinetic energy of each electron is
K1 = ( 1/2) m v 12
K2 = ( 1/2) m v 22
Therefore, the total energy of the incident is,
In terms of keV,