In J. J. Thomson.s experiment, what observations were found when
(a) a small obstruction was placed in the path of cathode rays.
(b) a paddle wheel is placed between cathode and anode. What were the conclusions drawn on the basis of these observations?

What would you conclude from the observation that cathode rays rotate a light paddle wheel placed in their path ?

While studying the properties of cathode rays in a discharge tube a student placed mica wheel moundted on an axle in the path of the rays .What would happen to the wheel? What conclusions can be drawn from it?

Thomson's analysis of cathode ray experiment led him to conclude that electrons were fundamental particles. e//m ratio for particles in cathode rays was found to be independent of the nature of the gas taken in the tube.

In a experiment it was found that the string vibrated in three loops when 8 g were placed on the scale pan. What must be placed on the pan to make the string vibrate in six loops? Neglect the mass of the string and the scale pan.

In Melde's experiment , a string vibrates in 3 loops when 8 grams were placed in the pan.What mass must be placed in the pan to make the string vibrate in 5 loops ?

The existence of negatively charged particle in an atom was shown by J.J. Thomson as a result of the studies of the passage of electricity through gases at extremely low pressure known as discharge tube experiments. When a high voltage of the order of 10,000 volts or more was impressed across the electrodes, some sort of invisible rays moved from the negative electrode to the positive electrode these rays are called as cathode rays. Cathode rays travel in straight path in absence of electrical and magnetic field . Cathode rays consist of material part and charged particles? Cathode rays produce X-rays and light is emitted when they strike on ZnS screen. Cathode rays penetrate through thin sheets of aluminium and other metals . They affect the photogenic plate and passes heating effect when they strike on metal foil. The raito of charge to mass i.e charge/mass is same for all the cathode rays irrespective of the gas used in the tube. The existence of positively charged particle in an atom was shown be E. Goldstein. He repeated the same discharge tube experiments by using a perforated cathode. It was observed that when a high potential difference was applied between the electrodes, not only cathode rays were produced but also a new type of rays were produced simultaneoulsy from anode moving towards cathode and passes through the holes or canal of the cathode. These termed as canal rays or anode rays. These rays travel in straight lines and consists of positively charged particles. These rays have kinetic energy and produces heating effect also. The e/m ratio of these rays is smaller than that of electrons. Unlike cathode rays, their e/m value is dependent upon the nature of the gas taken in the tube. These rays produced flashes of light on ZnS screen and can pass throughs thin metal foils. They can produce physical and chemical changes and are capable to produce ionisation in gases. Which is not true with respect to cathode rays?