Question

define magnitude with example and diffence between electrons and cathode ray?

Answer 1

Magnitude is the measure of amount of physical quantity . Magnitude of any physical quantity is always scalar.
For eg: Velocity is the Vector quantity because it defines the directional speed.. But it's magnitude that is speed is a scalar quantity. Velocity = 100 ms^-1 towards North (vector quantity)
magnitude = 100 ms^-1

Electrons are simply Negatively Charged particles in an atom.
Cathode rays are a beam of electrons coming out from cathode towards anode ,when an electric charge is passed through gases at a very low pressure.