Discovery of Anode Rays
- The discovery of anode rays is credited to the German scientist Eugen Goldstein in the late 19th century.
- Goldstein observed a glow in a cathode ray tube when a perforated anode was introduced.
- He called these rays "Kanalstrahlen" or canal rays.
- Goldstein's experiments were a continuation of the earlier work done by J.J. Thomson on cathode rays.
- Cathode rays are streams of electrons that are emitted from the cathode in a vacuum tube.
- Goldstein's experiments with cathode rays led him to discover that there were also positively charged rays moving in the opposite direction, which he called anode rays.
- Anode rays are formed when residual gas molecules in the cathode ray tube are ionized by the high-speed electrons from the cathode.
- These positively charged ions are attracted to the negatively charged anode, creating a glow or fluorescence.
- Goldstein's discovery of anode rays provided further evidence for the existence of charged particles and contributed to the development of the understanding of atomic structure and the nature of electricity.
Therefore, the correct answer is B: Goldstein.

Anode Rays: Discovery Overview
Anode rays, also known as positive rays, were first discovered by the German physicist Johann Wilhelm Hittorf in 1869, but it was Goldstein who later conducted significant experiments that led to a better understanding of these rays.
Key Contributions by Goldstein
- Experimentation: Goldstein utilized a gas discharge tube setup, where he observed the behavior of rays emitted from the anode when a high voltage was applied.
- Observation of Positive Particles: He noticed that in a vacuum tube, rays traveled in the opposite direction to the cathode rays (which are negatively charged), indicating that these rays were composed of positively charged particles.
Characteristics of Anode Rays
- Nature of the Rays: Anode rays consist of positively charged ions and are produced when high-energy electrons collide with the gas molecules in the discharge tube.
- Mass and Charge: The ions that make up anode rays can vary in mass and charge depending on the gas used in the tube.
Significance of the Discovery
- Understanding Atomic Structure: Goldstein's work with anode rays contributed to the understanding of atomic structure and the existence of positively charged particles, leading to later developments in atomic theory.
- Foundation for Future Research: This discovery laid the groundwork for further studies in nuclear physics and the behavior of ions in electric fields.
In conclusion, while Hittorf initiated the discovery of anode rays, it was Goldstein who significantly advanced the understanding of these positive rays, making him the key figure in their discovery.