Chapter 26.1, Problem 10SSC

To determine

To Describe:The process through which the cathode-ray tube used by J.J. Thomson forms an electron beam.

Answer to Problem 10SSC

The electron beams are produced when the collection of electrons pass through slits in the anodes in the cathode-ray tube.

Explanation of Solution

Introduction:

British physicist J.J. Thomson was able to determine the charge to mass ratio i.e. $\left(\frac{q}{m}\right)$ of an electron. Knowing both $\left(\frac{q}{m}\right)$ and the charge of an electron $\left(q\right)$ , he was able to calculate the mass of an electron. For this purpose, electron beams were used in his experimental setup and the electron beam is a collection of electrons.

To measure the charge to mass ratio of an electron, J.J. Thomson performed an experiment. For this experiment, he sued a cathode ray tube which can generate a stream of electrons. Within the cathode ray tube an electric field is created by the greater potential difference between the cathode and anode. The cathode in the tube emits the electrons, and these electrons are accelerated against the anodes by the electric field in the cathode ray tube.While an electron accelerates towards the anodes, few of these electrons pass through the slits in anodes forming a narrow beam which is called electron beam.

Conclusion:

Hence, electron beams are produced when the collection of electrons pass through slits in the anodes in the cathode-ray tube.