Question

what did j. j. thomson observe when he applied electric voltage to a cathode ray tube in his famous experiment?
the stream of cathode ray particles was moving very slowly.
the glass opposite of the negative electrode started to glow.
the electric voltage had little effect on the stream of particles.
the tube contained two pieces of metal that served as electrodes.

Explanation:

• For option A: Cathode ray particles (electrons) move at high speed, so this is incorrect.
• For option B: In J.J. Thomson's cathode ray tube experiment, when voltage is applied, the cathode rays (electrons) travel from the negative electrode (cathode) to the positive electrode (anode), and the glass opposite the negative electrode glows due to the impact of the rays, which is a key observation.
• For option C: The electric voltage deflects the cathode ray particles (since they are charged), so the voltage has a significant effect, making this option wrong.
• For option D: Stating the tube has two metal electrodes is a description of the apparatus, not an observation during voltage application.

Answer:

B. The glass opposite of the negative electrode started to glow.