Basic Questions in Physics
1) Define 'matter'?
The things we think there are in the universe.What ever the physical universe is made up of.The study starts from here that there are two kinds of matter.We call it positive and negative.Like kinds repel and unlike kinds attract.
2) Then Why don’t two people, attract or repel when they stand near each other ?
Because they are evenly mixed bunch of positives and negatives. In other words , they are electrically neutral.So perfect is the balance of attraction and repulsion(of course the number of protons and electrons) that when you stand near someone else,you don’t feel any force at all. Neutral things don’t attract or repel neutral things.
3)Then where does the electrical force manifests?
When we look at matter on a small scale, a net force can arise,if a negative charge of one piece,is closer to the positive, than to the negative charge of the other piece(Inverse square law).A net attraction results.The force that holds the atoms together, and the chemical forces that holds the molecules together,are really electrical forces,acting in regions where the balance of charge is not perfect, or where the distances are very small.
4)Why protons and electrons do not get on the top of each other,if they attract?Instead they keep a distance.?
Of course there may be many electrons and many protons,in an atom.Net state will be the result of the sum of the individual repulsive and attractive forces. Or by a sacred law in quantum mechanics,(uncertainity principle), if we confine electrons very near to protons,it will result in a large momentum of electrons.If protons and the electrons are on the top of each other,then there will be infinite momentum for electrons,which is not relevant.(yah ! laws are difficult for free people to understand.But there are laws.(because we are bound in the universe. Actually in Earth))
5)What holds the nucleus (cluster of protons) together?
The responsible forces are called nuclear forces,which are greater than electrical forces and are able to hold the protons together in spite of the electrical repulsion.They are short range forces
6)Then why nucleus splits sometimes?(like nuclear fission)
Since the nuclear forces are short range, it mainly act between each particle and its nearest neighbor,while the electrical forces act over larger distances,giving a repulsion between each proton and all of the others in the nucleus.the more protons in a nucleus,the stronger is the electrical repulsion,until as in the case of uranium,the balance is so delicate that the nucleus is almost ready to fly apart due to the repulsive electrical force.
7)Nuclear energy is really electrical energy. Why?
Nucleus splits due to electrical repulsion.So the energy released is actually electrical in origin
8)What holds an electron together ?IF an electron is made up of the same kind of substance,then each part should repel each other.Why didn’t it happen?
In electromagnetic theory an electron is just a point.So it doesn’t act on itself.Of course the correct answer is not that.The creator of the electron knows that(Excuse me)
9)In matter ,there are conductors and insulators . How?
Flow of electrons is called electric current. The matter where electrons are free to flow(not held tightly to nucleus) are called conductors.When the electrons are held tightly to individual atoms , they cannot flow. So insulators
10)What happens when matter is moving?
Almost all time matter is moving.Electrical forces also depend on the motion of charges in a complicated way.One part of the force between moving charges we call the magnetic force.It is really one aspect of an electrical effect.So we call the theory as electromagnetic theory.