<span>They are poor insulators because the electrons in the atom are tightly bound and unable to move between other atoms.
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Explanation:
It is given that,
Mass of an electron, 
Initial speed of the electron, 
Final speed of the electron, 
Distance, d = 5 cm = 0.05 m
(a) The acceleration of the electron is calculated using the third equation of motion as :



Force exerted on the electron is given by :



(b) Let W is the weight of the electron. It can be calculated as :



Comparison,


Hence, this is the required solution.
A gas has to become ionisied in order to become a conductor. It must have a chain reaction in which atoms in it became unstable, in which they loose stabile electronic configuration. In order for a gas to become a conductor, it must have free particles, and it can happen only in ionisied gas.