How can we prove that the electrons carry a negative charge?

Why does a light paddle wheel placed in the path of cathode rays begin to rotate, when cathode rays fall on it?

a) What happens in the discharge tube if a high voltage is applied at a gas pressure of 760 mm mercury?

b) What will happen if the pressure is reduced to 0.01mm of mercury?

Selvi took a conical flask, put some ice cubes into it and closed it with a stopper. Then, she found the weight of the conical flask using a balance. Its weight was 150 g. After some time, ice started melting and turned into water. She weighed the flask again. The weight was 150 g. What inference would you draw from this experiment?

Kannagi, Goutam, David, and Saleem collected different samples of water from a well, a pond, a river and underground water. All these samples were sent to a testing laboratory. The test result showed the ratio of hydrogen to oxygen as 1:8.

a) What conclusion would you draw from the above experiment?

b) Which law of chemical combination does it obey?