J. J. Thomson originally referred to the rays produced in his apparatus (Fig. 1A.2) as canal rays.

Question:

J. J. Thomson originally referred to the rays produced in his apparatus (Fig. 1A.2) as “canal rays.” The canal ray is deflected within the region between the poles of a magnet and strikes the phosphor screen. The ratio Q / m (where Q is the charge and m the mass) of the particles making up the canal rays is found to be 2.410 * 10⁷ C·kg^–¹ . The cathode and anode of the apparatus are made of lithium, and the tube contains helium. Use the information inside the back cover to identify the particles (and their charges) that make up the canal rays. Explain your reasoning.

Figure 1A.2

Electron source Electron beam Screen Magnet