Attraction between comb and paper bits It is a common phenomenon that a comb, when rubbed against dry hair, gains electric charge and attracts paper bits. My question is that if the comb induces an opposite electric charge on the nearer end of the electrically neutral paper bits, why do paper bits get attracted to the comb as the like charges that develop on the farther end of the paper bits repel the comb with equal magnitude as the force of attraction between the nearer end and the comb. Therefore, the net electrostatic force on the paper bits should be zero i.e. the paper bits should remain stationary.
 A: You must note that the electrostatic force equation is :
$$F = \frac{kq_1q_2}{r^2}$$
The term $r^2$ matters the most.
The positive charge on the comb (let's just assume it as positive) is closer to the negative charge on the paper and farther from the positive charge on the far end of the paper.
Beacause of this separation differences the paper bit gets attracted to the comb.
A: Your assumption that the repulsive and attractive forces are equal in magnitude is misguiding you.

When the comb is rubbed against dry hair, electrons from hair jump into the comb. This gives comb a negative charge, leaving your hair with slightly positive charge on them. When the tiny bits of paper are brought in vicinity of the negatively charged comb, the charges on the initially neutral paper rearrange. Paper is an insulator, so actually it's just the negatively charged electrons that shift a little bit towards the farther end of each atom leaving a slight positive charge on the end closer to the comb and slight negative charge is attained to the farther end of an atom (where the electrons have moved to). Therefore, each atom becomes an electric dipole.

Applying the expression for electrostatic force
$$F=\frac{kQ_1Q_2}{r^2}$$
 where k is a constant, Q1 and Q2 are charges on two different bodies separated by a distance r. So greater the r is, smaller is the force. Hence, the attractive force on the charges in the nearer part is greater than the repulsive force in magnitude, as k, Q1 and Q2 are constants.
Thus, the paper bits are attracted towards the comb. The quadratic relationship makes this effect change very substantially with distance, so even the distance differences measured in angstroms can result in a visible effect.
