Give examples of non-conductors and conductors.

$(a)$ $A$ comb run through one's dry hair attracts small bits of paper. Why? What happens if the hair is wet or if it is a rainy day? (Remember,a paper does not conduct electricity.)
$(b)$ Ordinary rubber is an insulator. But special rubber tyres of aircraft are made slightly conducting. Why is this necessary?
$(c)$ Vehicles carrying inflammable materials usually have metallic ropes touching the ground during motion. Why?
$(d)$ $A$ bird perches on a bare high power line,and nothing happens to the bird. $A$ man standing on the ground touches the same line and gets a fatal shock. Why?

Give reason: 'Small and light pieces of paper are attracted by a comb run through dry hair.'

Assertion $(A)$: Electromagnetic force is enormously strong as compared to gravitational force. Yet,gravity dominates in large-scale phenomena (e.g.,formation of galaxies).
Reason $(R)$: Existence of positive and negative charges makes matter mostly electrically neutral.
Which of the following is true?

For what type of charge distribution,electric field can be obtained by using Coulomb's law and superposition principle?

Why can only electrons transfer from one body to another body in frictional electricity?