Viva Questions J J Thomson experiment charge to mass ratio of the electron

Viva Questions charge to mass ratio of the electron experiment

1Q. What Is Cathode Ray Tube (CRT)?

2Q. What is electron gun in CRT?

3Q. Why do we use filament in CRT?

4Q. How electrons emits from the cathode?

5Q. How do you accelerate electrons in CRT?

6Q. What is the role of cathode and anode in CRT in reference to the emission of electrons?

Questions related to the Deflecting Section of CRT

7Q. How deflecting plates effect the path of electron beams?

8Q. Does electron beam deflects by the electrodes only ?

9Q. What is the formula for force on charge particle in the presence of electric field?

10Q. What is the formula for force on charge particles in the presence of Magnetic field?

11Q. In the presence of uniform magnetic field when electron beam enter into the field perpendicularly, what type of path electron beam will follow?

12Q. How centripetal force contribute in the question 11?

13Q. How to determine one the radius r in the centripetal force formula, what is concept?

14Q.Does forward or reverse biasing can effect the path of electron beam?

Screen of Cathode Ray Tube

15Q. What type of material produce the ligt on screen of CRT when electrons strike ?

16Q. Does magnetic coil is already built in Cathode Ray Tube?


Does magnetic field source is inbuilt in CRT to produce the magnetic field or we use it from externally?

17Q. Suppose you deflected the electron beam on screen by some distance, can you bring at original position by the external electric or magnetic field at original position?

18Q. In reference to 17 th question which field is more suitable to handle this problem, electric or magnetic and why?

19Q.  What is the standard value of charge to mass ratio of the electron in JJ Thomson method.

20Q. What formula you have used to determine the charge to mass ratio of the electron and what is the origin of it?

Magnetic Field Determination

21Q. Are you using Helmholtz’s Coils or permanent bar magnets in this experimet to balence the electric force on electron?

22Q. If you are using Helmholtz’s Coils how you will determine the magnetic field, what is the formula used for it?

23Q. If you are using bar magnet then how?

24Q. Does earth’s magneetic field depeds on the lattitude and altitude?

25Q. How do you will calculate the earth’s magnetic field at your place?

26Q. Does magnetic compass in mobile phone can tell approximate value of earth’s magnetic field?

27Q. What is unit and approximate value of earth’s magnetic field?

These are some basic viva questions, which one should know to determine the value of charge to mass ratio of the electron in J J Thomson’s experiment. If you don’t have answer of any question you can ask for help to me. Also, if you have information related to these questions it means you know almost everything about the experiment.

Dr Sushil Kumar

Dr. Sushil Kumar, a physicist, an eminent researcher and a teacher for the benefit of students and fellow physicists alike. Vyom Hans is an effort to create a better platform and also to help the students to be able to have content at their hands whenever they want, online. Dr. Sushil continues to upload his lectures and post articles about latest researches in physics, academic, physics education, and also lessons about daily life and how physics define every aspect of our everyday movement and life.

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