Physics · Electric Charges And Fields · NEET
No. The glass rod becomes positive and the silk becomes negative, but no new charge is made. Electrons simply move from the glass to the silk. What the glass loses, the silk gains. Before rubbing the total was zero, and after rubbing the total is still zero (+q on glass and -q on silk add to zero). This is conservation of charge in action.
It means that in an isolated system (one where charge cannot leak in or out), the total charge stays constant with time. Charges can move around and get redistributed between bodies, but if you add up all the plus and minus charges, the total is fixed. It only refers to the NET charge, not the number of charged particles.
No. If one sphere has +8 uC and another has -2 uC, the total is +6 uC. After they touch, the charge redistributes, but the two together still hold +6 uC. Conservation fixes the TOTAL; how it splits depends on their sizes. This is why the NEET 2019 charge-transfer question keeps the sum constant.
No, they are different rules. Conservation says the TOTAL charge of a system never changes. Quantisation says any charge must be a whole-number multiple of e, that is Q = ne. One is about the total staying fixed; the other is about charge coming in fixed packets. NEET often tests both in the same chapter, so keep them separate.
No charge is destroyed. If +q meets -q, they may neutralise so the object shows zero net charge, but the individual charges are still there, just cancelling. The total (which was already zero) stays zero. Even in particle physics, when an electron and positron annihilate, the equal and opposite charges add to zero before and after, so charge is still conserved.
Two point charges A and B, having charges +Q and -Q respectively, are placed at a certain distance apart and the force acting between them is F. If 25% of the charge of A is transferred to B, then the force between the charges becomes:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
The total electric charge of an isolated system remains constant. Charge can be transferred from one body to another, but it can neither be created nor destroyed.
Rubbing a glass rod with silk: electrons move from glass to silk, glass gets +q and silk gets -q. The total was zero before and stays zero after, so charge is conserved.
Many numerical questions (like charge sharing and charge transfer) start by writing total-charge-before = total-charge-after. This one step decides the new charges before you apply Coulomb's law, so it is a fast, high-yield check.
Yes. Even in radioactive decay or electron-positron annihilation, the total charge before a reaction equals the total charge after. It is a universal conservation law.
