MCQ Detailed View

Cathode rays are streams of high-speed electrons that are emitted from the cathode (negative electrode) in a vacuum tube when an electric current passes through it. Since electrons are negatively charged particles, cathode rays carry a negative charge. They were first discovered by J.J. Thomson in his experiments with discharge tubes, which led to the discovery of the electron.

Anode rays, also known as canal rays, are positively charged particles emitted from the anode. They consist of protons or other positive ions formed when gas molecules inside the discharge tube lose electrons. These rays are not negatively charged.

Gamma rays are high-energy electromagnetic waves with no mass and no electric charge. They are neutral and travel at the speed of light. Canal rays are similar to anode rays and are also positively charged.

Cathode rays are responsible for many important discoveries in atomic physics. They travel in straight lines in the absence of electric or magnetic fields, produce a greenish glow on a fluorescent screen, and can be deflected by electric and magnetic fields due to their negative charge. These observations confirmed that cathode rays consist of negatively charged particles.

The behavior of cathode rays is fundamental in understanding atomic structure and the nature of electric charge. They were key in developing early models of the atom and are still used in devices like cathode ray tubes (CRTs), old television screens, and oscilloscopes.

Among the given options, only cathode rays consist of negatively charged particles. Anode rays and canal rays are positively charged, while gamma rays are electrically neutral electromagnetic radiation. Therefore, the rays with negative charge are cathode rays, as they are streams of electrons emitted from the negative electrode under low-pressure conditions.