wht is Quantum Size Effect? plz explain...........?

Answer 1

You're probobly getting this from a second-hand source because real phsyicists don't talk about "Quantum Size Effects". What that term is probobly refering to is related to the Uncertainty Pricipal.

For very small particles, there is a minimum certainty to which thier positions and velocities can be known. Knowledge of one percludes knowledge of the other. This priceipal holds for other properties as well, such as field strength and field flux.

This means that at tiny, tiny scales, things start to get jittery and unpredictable. Below the plank length (10^-35 meters), space itself gets so convoluted that dimensions and direction have no meaning. If you were that small, you could see the back of your head. You could reach out and touch the inside of your spleen. Things are really bizzare at that scale.

The upshot is that subatomic particles exibit interesting and useful behaviors, such as passing through an apparently impermeable surface ("quantum tunneling") or "communicating" with another particle instantly at any distance, ("quantum entanglement"). These are probobly what is meant by "Quantum Sise Effects"

Answer 2

If I recall any of this correctly and I likely don't, quantum physics only normally happen at the subatomic level, with particles smaller than atoms, like electrons (electricity), protons (hydrogen nuclei) and neutrons.

If you are referring to a "Quantum Size Effect" you are likely referring to something going on *right at* the mathemetical boundary where combined Newtonian/Ensteinian physics ends, and where quantum physics begins. Some atoms on the larger end of the Periodic Table of Elements, your metals and rare-earths that are more massive than Platinum I think, have some Quantum Size Effects going on because their *outer* valance electron shells are actually large enough to operate in Newtonian/Ensteinian physics more so than they would in Quantum....

But it has been a *LONG* time since I read that article....let me get you some links to look up, and keep in mind the articles in question might be from four or five years ago.