The positron is a particle with the same mass as an electron but charge +e. A positron in a bubble chamber moves perpendicular to a 4.5T magnetic field.
If the positron's kinetic energy is 28eV , what's the radius of its trajectory in the bubble chamber?
A proton takes 99.0?s to complete one orbit around a 14.5 m diameter cyclotron.
What's the cyclotron's magnetic field?