King E

It was about epsilon, in case of refraction.

??

Let’s start out with a glass with no electric field in it. Now we we impose an electric field on the glass by sending light in it. Then, how do the charges in the glass set up their own counterbalancing electric field in opposite direction that results in reducing the total electric field?

I learned from a source that when external magnetic field is applied, parallel spin/spin up has lower energy than spin down. But why? How does this relate to two like poles of magnets facing each other and two unlike poles facing each other? Source:https://mriquestions.com/energy-splitting.html

What about in case of O₂ ? Or H₂ ? The electronegativity is same. Which atom will get partial negative charge and which will get partial positive charge in the above mentioned cases? Each hydrogen atom in H2S , no doubt gives 1 electron to sulphur but also takes 1 electron from sulphur. Similarly the sulphur atom takes 1 electron from each hydrogen atom but also gives 1 electron to each hydrogen atom. So why isn't the oxidation state of each hydrogen atom -1 and that of sulphur +2 in H2S ?

How is the oxidation state in covalent compounds calculated ? For example, in H₂S, why does hydrogen have an oxidation state of +1 and sulphur has oxidation state of -2 as the electrons are being shared ? Can hydrogen have oxidation state of -1 and sulphur +2 (because the electrons are shared) ?

If you bump an electron to H- ion, can't the electron just enter the empty L shell by releasing energy?

What I meant to say is can a Hydrogen -2 ion be formed?

In hydrogen, why cannot electrons enter an empty shell after the K shell is filled?

I did. Some people are saying that its a physical change and some are saying that it is a chemical change. In a solution the constituents exhibit individual chemical characteristics. You are saying that new chemical species are formed. So will the "NaCl in water " solution have different chemical properties from its constituents(NaCl and H2O)? i.e. is a "NaCl in water" solution a new compound with respect to NaCl or H2O ? And is the ion surrounded by water molecules (solvation shell) a new compound?

It ain’t. The interaction of water molecules.

How?

Is the solvation of salt (NaCl) in water a chemical reaction?

Why doesn’t that happen by conduction, when the molecules below vibrate upon heating and collide with each other they transfer energy all the way through other molecules to the surface molecules?

I heard, molecules only at the surface of the liquid evaporate. But do the molecules below the surface of the liquid evaporate? Suppose we heat a container containing a liquid from the bottom. So molecules at the bottom of the container will have higher kinetic energy than the molecules on the surface. How will the molecules on the bottom escape as vapours?