Answer and Explanation:
(a) The attached image below shows the diagram of a CRT in the helmholtz coils and well labelled with details
(b). The electron will follow a circular path which travels along under constant magnetic field

where m = mass of electron, V = velocity of electron, q = charge of the electron and B = magnetic field strength
60 RPM equals one hertz (i.e., one revolution per second, or a period of one second). The SI unit for period is the second.
Answer:
chemical potential of a species is energy that can be absorbed or released due to a change of the particle number of the given species, e.g. in a chemical reaction or phase transition.
Explanation:
It hardens because you are pressing it against something.