Cathode rays are beams of?
electrons
protons
anions
neutrons

Cathode rays are beams of electrons generated in a vacuum tube.

hope this will help you

Electrons

Explanation:

Electrons are produced when light with enough energy is directed onto the cathode where electrons are ejected as beam towards the screen.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

c. 4.54 x 10–12 j happens to be correct