# School:Physics/Help desk

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## Inorganic Chemistry: Radial distribution functions of hydogenic orbitals

Question: Which orbital, 3p or 3d, gives an electron a greater probability of being found close to the nucleus? I know that the answer is 3p, but I don't know how I can explain this correctly. Can you help me with that?

Alchemist 09:19, 27 June 2007 (UTC)

Question has been answered at the general Wikiversity Help Desk: Wikiversity:Help_desk#Inorganic_Chemistry:_Radial_distribution_functions_of_hydogenic_orbitals]. StuRat 04:55, 29 June 2007 (UTC)

## Big bang

with out an external force,how can big bang occur? (The preceding unsigned comment was added by 59.91.251.154 (talkcontribs) 05:39, 18 May 2008)

You're quite correct that under traditional W:Newtonian physics, it would be impossible. However, this may not be true under W:quantum mechanics and newer variations, like W:string theory and W:brane theory. For a similar case, it would also seem to be impossible for matter to leave the area of a W:black hole inside the W:event horizon, yet it does, via W:Hawking radiation. StuRat 14:19, 18 May 2008 (UTC)

## Increase the electrical conductivity of water

How do I increase the electrical conductivity of water while maintaining a non-corosive envirenment, or a minimal corosive envirenment?

--69.150.135.30 19:51, 18 June 2008 (UTC)

Adding a bit of salt is the easiest way. You can add just about anything to pure water to increase it's electrical conductivity, though. For example, vinegar might work. I suggest you get an electrical meter, put the leads on either side of a beaker of water, then add a test substance to see how the electrical resistance changes. StuRat 01:20, 19 June 2008 (UTC)

## Higgs field

how is the presence of the Higgs field as an everpresent uniform situation different from the ether that a michaelson trounced?

As I understand it, W:Luminiferous aether was supposed to be a fluid which through light waves could travel, much like water is the fluid through which ocean waves travel. It turned out not to exist, and the wave/particle duality model of light was developed to explain how light could travel through a vacuum, instead. (W:Albert Michelson, in the famous w:Michelson–Morley experiment, attempted to prove it's existence, but ultimately proved it's non-existence.) The W:Higgs field, on the other hand, is a theory to explain how particles gain mass, much like particles can gain an electrical charge when passing through an electromagnetic field. StuRat 06:54, 7 August 2008 (UTC)

## blue shift and big bang theory

If the universe is expanding because of the Hubble red shift, why are blue shifted galaxies heading in our direction?205.188.117.199 Larry Alan Hale

Red shift means the object is moving away, and blue shift means it is moving towards us. So yes, since the universe is expanding, we would expect most galaxies to be moving away from us. However, the galaxies do have gravitational attraction for each other, so that those which are near each other tend to have gravitational effects which are more powerful than the overall expansion of the universe. Thus, some nearby galaxies are actually moving towards us. This doesn't necessarily mean a collision will result, as these galaxies can fall into orbits around each other. If you think about the Doppler Effect for sound, you can't tell from it when something is headed exactly toward you, such that it will hit you, but only whether it is generally headed toward or away from you. The red or blue shift would be stronger if it was headed exactly toward or away from you, but, since the speed is unknown, we don't have any basis for comparison of the amount of shift. StuRat 12:28, 29 August 2008 (UTC)

## electromagnetism

What is the magnetic field at the centre of the hydrogen atom? Is it the same as a single loop of wire?

The most common isotope of hydrogen has one proton at the center with one electron "in orbit" around it. The force which attracts the negatively charged electron to the positively charged proton is essentially the same as "static electricity", which attracts bits of paper to your hair after combing it, for example. The magnetic field caused by an electromagnet such as you describe is related, in that it's still the electromagnetic force involved. However, it's not a permanent charge in the wire, but rather a moving charge (electrons flowing through the wire), which causes the temporary magnetic field. Thus, as soon as the electrons stop flowing, the magnetic field collapses. StuRat 19:13, 8 March 2009 (UTC)

## How was the universe created?

```Is the universe created according to the following theories:
A. The Big Bang Theory
B. Dust Cloud Theory
C. Divine Theory
D. Pulsating Theory
F. Big Crunch Theory
```
C is a purely religious theory, while the rest are scientific (although some are old scientific theories which have since been disproven). The Steady-State theory is that the universe was always pretty much the same, while red-shifts show it's actually expanding, so that's not true. Therefore, if it's expanding, that means it came from a point, which is basically the Big Bang theory. The Big Crunch and Pulsating/Oscillating Universe theories have to do with how it ends, by coming back to a point (due to gravity) and then possibly exploding again and again, forever. However, the latest measurements seem to show that the universe is expanding at an accelerating rate, meaning it will never come back together. The new death of the universe has been called the "Big Freeze", because, as it expands, the universe also cools, until it eventually gets close to absolute zero. The Dust Cloud theory is more of a model for the formation of solar systems and galaxies than for the whole universe. So, given those choices, the best scientific answer is the Big Bang. StuRat 15:06, 9 December 2009 (UTC)

I would respect you for choosing the Big Bang Theory. But I believe in Dust Cloud theory. I made a theory to support it but it has no mathematical calculation which means it can be denied thoroughly because I depend on physical evidence. No hard feelings, just defending the Dust Cloud Theory. Christian Louie M. Pajaron 12:25 Philippines February 3, 2010

There is a third way to look at how the universe was created. Besides the religious (fantasy) and scientific (backed by mathematics). This is the realistic way which does not rely on either fantasy or mathematics. But considers only if it is realistically possible or not. I am developing such a theory right here at WV. Called ACR. I would welcome any POV. --Martin Lenoar 01:24, 25 November 2010 (UTC)

## Water

Is water an insulator or a conductor? Christian Louie M. Pajaron

Pure water is an insulator. However, adding just a few impurities makes it into a conductor. Since water in rivers, lakes, and oceans (and tap/bottled water) all has those impurities in it (like salts and other minerals), it all acts as a conductor. So, unless you happen to have some distilled water handy, you won't be able to use it as an insulator. Even if you start with distilled water, it's easy to add impurities when you pour it into a container and put electrodes in it to test electrical resistance. Everything must be spotlessly clean to get a reading that shows it to be an insulator. StuRat 05:38, 8 January 2010 (UTC)

Ah, so that's why it's dangerous to swim in the sea when there's a thunderstorm.

Yes, sea water is definitely a conductor. StuRat 14:18, 27 January 2010 (UTC)
Pure water has a slight conductivity of about 5.5 μS/m, typical drinking water in the range of 5-50 mS/m, while sea water about 5 S/m. 84.209.89.214 (discuss) 10:51, 17 August 2014 (UTC)

## plz help me..

Solve problem using circuit theorems to calculate current and voltages in circuits

Wikipedia: Ohm's law is useful. 84.209.89.214 (discuss) 10:58, 17 August 2014 (UTC)