Figure 1.31 shows the trace of the path of a charged particle in a bubble chamber. Assume that the magnetic field is into the plane of the paper with magnitude 0.4 T. The smooth spiral path occurs because the particle loses energy in ionizing molecules along the path.
a. Which part of the path corresponds to higher kinetic energy for the particle? Inner or outer part of spiral.
b. Is the charge positive or negative?
c. The radius of curvature ranges from 70 mm to 10 mm. What is the range of values of the magnitude of momentum if the magnitude of the charge is e?

Explanation

(a) When the particle begins its motion, the outer part of the
spiral corresponds to high kinetic energy.
(b) Charge is positive.
(c) `p_1=qBr_1=exx0.4xx70xx10^-3=exx28xx10^-3`
`p_2=qBr_2=exx0.4xx10xx10^-3=exx4xx10^-3`
The range of momentum is `4exx10^-3 kgm//s to 28exx10^-3`
`kgms^-1`.