Science & Mathematics - 28 December 2007

Of L.E.D. light emitting diodes? I understand filaments and arc lights fairly well but light emiting diodes are beyond my understanding.

2007-12-28 12:29:58 · 2 answers · asked by Anonymous in Physics

First, I waited in the waiting room while the receptionist joked about how the doctor doing my procedure would have a long needle, which he would have to stick me with, and of course, that was a lie. Then I went into a hospital room to be prepared for the procedure. The nurse did stick me with a needle, twice, I might add, but it was just one of those intravenous drips so that anesthetics could be given to me. Then I waited for about 15-20 minutes in my hospital gown, with the opening on the "backside," and in my hospital footies, which had smiley faces on them that helped me walk with a grip on the floor. However, there was no need to walk, as there was a nice looking male nurse who came to roll me into the room where my procedure would be done. I laughed to calm my nerves as an Anesthesist stated to me how I would be sedated, immediately, after she injected me. The male nurse, of all people, was still there preparing the scope that would be inserted into my 2007-12-28 12:29:26 · 4 answers · asked by Suzy Q 2 in Medicine

1. 0%
2. 25%
3. 50%
4. 100%

2007-12-28 12:29:22 · 3 answers · asked by Anonymous in Chemistry

1a) Put this equation in mx+b form: 3y=x-15

1b)write the equation of a line this is parallel to the given line.

2007-12-28 12:24:03 · 7 answers · asked by Anonymous in Mathematics

1. Why do living things CARE if they have offspring ? I mean life is a series of chemical reactions right ? But why would a conglomeration of chemicals go through all this trouble to procreate? I mean stars and planets don't. Rocks don't seek to preserve rockdom and water does not attempt to ensure there will always be wetness so why do organisms seek to recreate themselves ?
2. Why the variety ? Evolution doesn't cut it. When the first life forms became sussessful why didn't it stop there? I mean there are types of algea that have been around for over a BILLION years. Long before complex organims. So why did complex organisms develop ? What purpose could that possibly serve the original ones from which they are descended?
3. Since human beings are just intelligent animals everything we do is natural right ? Why should we care about other creatures beyond the extent to which it is to our benefit?

2007-12-28 12:23:15 · 4 answers · asked by Vince Foster 4 in Biology

just to clarify:

so an element has one electron shell right?

and that electron shell has sublevels

so like in the Bohr model when they have circles around the nucleus.. each circle is an orbital which is different from a shell because a shell refers to all of the orbitals??

and those circles start from s and end at f at most?

can anyone clarify all this

2007-12-28 12:19:28 · 2 answers · asked by Anonymous in Physics

2007-12-28 12:19:23 · 2 answers · asked by hayk s 2 in Physics

material science

2007-12-28 12:18:07 · 1 answers · asked by Anonymous in Physics

material science

2007-12-28 12:16:07 · 2 answers · asked by Anonymous in Physics

I don't understand the Big Bang theory for these reasons:

1. Where did all this material, enough to make an entire Universe , come from ? What was it doing up until it condensed and exploded to become us ? Was there another universe previously or what ?
2. Where is the universe anyway ? I mean are there others ? does it have boundaries and how do you know ?

3. Why the heck would this stuff WANT to condense( I know of course that it did not have consciousness) into a big ball anyway ? Why wouldn't it just sit there since there were no heavenly bodies such as planets and stars to create a gravitational force ?

4. How can you KNOW any of this since noone was there to bear witness? It is all just educated guesses right? I mean we are talking TRILLIONS of light years of distance and BILLIONS of years of time. So how can we KNOW that the same laws that apply locally apply over such vast times and distances? We cannot possibly test these theories in real space/time.

2007-12-28 12:15:19 · 10 answers · asked by Vince Foster 4 in Astronomy & Space

find y' (prime) if x=tan(x+y)

2007-12-28 12:07:43 · 4 answers · asked by Venia c 1 in Mathematics

what is the derivative of this equation s(t)=sec√t

2007-12-28 12:04:12 · 2 answers · asked by Venia c 1 in Mathematics

The element indium has an atomic mass of 114.8 g and an atomic number of 49. Naturally occurring
indium contains a mixture of indium-112 and indium-115, respectively, in an atomic ratio of
approximately

(a) 6/94 (b) 25/75 (c) 50/50 (d) 75/25 (e) 94/6

2007-12-28 11:58:06 · 2 answers · asked by tmlfan 4 in Chemistry

2007-12-28 11:56:54 · 1 answers · asked by mackdr20032003 2 in Engineering

When the equation H2S + O2 --> H2O + SO2 is completely balanced using smallest whole numbers, the sum of all the coefficients is?
A)11
B)7
C)5
D)9

2007-12-28 11:56:23 · 1 answers · asked by Anonymous in Mathematics

It has a card talking about how purity is measured on it and on the back it says "This bag of ore is from one of the richest mines". The stones are gravel colored with a little bit of milky quartz and little sprinkles of gold. I really want to know what it is worth. I think it might be little sprinkles of gold in rocks.

2007-12-28 11:55:34 · 5 answers · asked by mini me 2 in Earth Sciences & Geology

I don't plan to poison no-one just curious.

2007-12-28 11:52:47 · 5 answers · asked by Gary88 1 in Botany

A)CaO
B)Al2O3
C)Li2O
D)CO

2007-12-28 11:52:12 · 1 answers · asked by Anonymous in Chemistry

A Young math teacher needed to make a little exrta money to support his family. To do this, he sold items during seasonla months. He buys a lot and starts the business with an ample amount of money in his pocket.

In Oct, the math teacher doubled hs money selling pumpkins. But, he had to spend $3000 setting up his stand and paying taxes

In Nov, he tripled his money selling turkeys. But, he had to spend 5400 on taxes.

In Dec, he quadrupeled his money by selling trees. But, he had to spend 7200 on taxes.

When the teacher came home he had $4800 in his pocket from the 3 months business. Was his wife happy or sad depending upon weather or not he made a profit?

1) How much money did he start out with?
2) How much did he gain or lose during the three holiday season?
3) Was his lovely wife happy or sad when he returned home with $4800 in his pocket at the end of Dec?

please please explain your answer. i REALLY need helpwith this!!

2007-12-28 11:51:06 · 2 answers · asked by taylor_travers098 2 in Mathematics

A) trigonal planar
B) T-shaped
C) bent
D) tetrahedral
E) trigonal Pyramidal

2007-12-28 11:49:51 · 4 answers · asked by Anonymous in Chemistry

I suppose that's been the thought in mind that stopped me from donating. Also, that it can expire in 42 days. I'd hate to think that my blood, which I thought would go to a meaningful cause, went to a stupid/meaningless one, especially after all that pain and effort.

But of course, I'll never know. :/

So, I thought, the only way I'd donate if someone I knew was hurt and they needed surgery. Or if I knew it was going to a free clinic. Unless, you tell me that I'm wrong.

2007-12-28 11:49:43 · 6 answers · asked by lialo 1 in Medicine

any suggestions?

2007-12-28 11:44:48 · 5 answers · asked by Anonymous in Other - Science

A) ionic solid
B) Network solid
C) metal
D) nonmetallic solid

2007-12-28 11:40:19 · 3 answers · asked by Anonymous in Chemistry

2007-12-28 11:36:24 · 3 answers · asked by Lisa K 1 in Mathematics

2007-12-28 11:35:53 · 4 answers · asked by Anonymous in Engineering

what does it mean when a baby has too much nitrogen in its kidneys

2007-12-28 11:35:32 · 1 answers · asked by italiaprincezza24 1 in Chemistry

ive never even been in snow b ut it looks amazing!

2007-12-28 11:34:48 · 11 answers · asked by Anonymous in Weather

Wouldn't our sun and all the things in the solar system have had to come from an exploded super nova in order for the metals and other more complex atoms to have formed?

2007-12-28 11:32:33 · 13 answers · asked by SpaceFan 1 in Astronomy & Space

i need some help about killer whales

2007-12-28 11:23:02 · 2 answers · asked by Anonymous in Zoology

2007-12-28 11:19:53 · 6 answers · asked by Danielle B 1 in Chemistry