A bubble chamber is a device that makes the path of a charged particle visible. When a charged particle with sufficient kinetic energy passes through a liquid, it will knock electrons off the atoms in its path. If the liquid is at a temperature above its boiling point, these ionized atoms become the nucleation point for a bubble to form, thereby marking the path of the particle. For the images in Figure Q20.13, the magnetic field was directed out of the page.
(a) Is the curve of the track in image 1 (on the left) consistent with that of a high-speed electron or of a high-speed proton?
(b) The particle trajectory in image 1 spirals inward. Explain why. 

Image 2 Image 1 3 Particle enters here Courtesy of Lawrence Berkeley National Lab (bo th)