A bubble chamber is a device used to study the trajectories of elementary particles such...

A bubble chamber is a device used to study the trajectories of elementary particles such as electrons and protons. Figure P20.36 shows the trajectories of some typical particles, one of which is indicated by a white arrow. Suppose this particle is moving in the direction indicated by the green arrow; the particle follows a curved path due to the presence of a magnetic field perpendicular to the plane of the photo. If is directed into the plane, is the particle positively charged or negatively charged?