The cathode ray experiments led to the discovery of which subatomic particle?

• A. Proton
• B. Electron
• C. Positron
• D. Neutron

Answer: (B)

Verified step by step guidance

1. Understand the historical context: The cathode ray experiments were conducted in the late 19th century to study the nature of cathode rays, which are streams of particles observed in vacuum tubes.
2. Recognize the key observation: Scientists noticed that cathode rays were deflected by electric and magnetic fields, indicating that they were charged particles.
3. Identify the particle's properties: The deflection showed that these particles had a negative charge and a very small mass compared to atoms.
4. Connect to the discovery: These negatively charged particles were identified as electrons, which are fundamental subatomic particles within atoms.
5. Conclude that the cathode ray experiments led to the discovery of the electron, not protons, neutrons, or positrons.