Homework Help

A planet with an atmosphere entirely consisting of O2 and atomic oxygen, O, is exposed to solar EUV radiation at a wavelength of λ = 80 nm. The O2 does not absorb this radiation but the atomic oxygen is ionized by it with an absorption and ionization cross section of σ = 1x10-18 cm2. The O+ ions rapidly undergo charge exchange with O2 to form O2+ ions, and the only electron and ion loss process is dissociative recombination of the O2+ ions O2+ e→O+O k1 = 1x10-8 cm3 s-1 If the solar flux is 1x10^11 photons cm-2 s-1 at 80 nm, the atomic oxygen scale height is 50 km and the O density is 1.6x10^12 cm-3 at 100 km, calculate the peak electron density of the resulting ionosph…

What are the reasons for why high blood pressure is a health concern?

i need to make a prodct for my project about Aids so i have gathered some hypodermic needles, african flags, gay symbols and that red ribbon but i need some more ideas for what other symbols i could use... anyone got an idea ?

hi , I'm having trouble in describing the difference between being overweight and obese after doing researches. And could you tell me the bad effects of being obese? thanks

Alright everyone? Just found out about this site on google and wondered if anyone can help me out with a stat test for my cswk. I have a set of results that goes a bit like this (this is a sample) Potato 1 8.3cm Shoot: 1.3cm Distance 0mm 5mm 10mm 15mm 20mm 30mm Cell 1 Average 2.8 2.8 4.6 5.4 3.2 …

hello i'm a high school student who is desperate, as usual i have lft my work till the last minute. i need to find out what the terms "multipotent" and "pluripotent" mean. Please help me!

Hi, I am new guy and I have a question that came across in my homework. Can you answer it? 1. In the productioin of beer, the raw material used is barley grains, which contain alarge amount of starch. When barley grains germinate, amylase is produced. The grains are then crushed and mixed with warm water. After several hours, yeast is added to the mixture for fermentation. a) After the crushed grains are mixed with warm water, why is it neccesary to wait for several hours before adding the yeast? Thanks

Well I have just recnetly started year 11 Physics, Biology and Chemistry. And I will turn to peoples help alot, so here is my first question: Volume is a derived quantity. From which fundamental quantity is volume derived? Thanks all

Hi was wondering if someone could help...doing some purification calculations. Ihave been given the specific activity the protein conc (mg/ml) and the volume extract (ml) and I need to work out the total activity and the % recovery of activity. e.g.the crude extract has vol extract of 150, protein conc of 6.4 and specific activity of 1.25 and % recovery is 100. How do I work out the total activity for the following purifications and the % recovery. Please help!! Thanks, barbie x

Can we remove the green color of leave of a green plant by heating the leaf with water(boil it)? I've got a leaf, one side is green in color and the other side is red. When I boil it, I observe the green color disappears gradually. Does this mean that chlorophyll decomposes under boiling?

Hey all i need to get multiple definitions of religion from some different sources for my studies of religion 2 unit class, i was wondering if someone could give me their definition to add to the short list i already have, thanks loads in advance. Tash

I'm doing a research paper about why evolution should be taught in schools, and ID should not. I've got it mostly planned out, and I've written most of my rough draft, and I was wondering if anyone had some good suggestions.

Hi, would anyone be able to give me some help on my biology essay? I have to write 650 words on “ The process of diffusion and its importance in living organisms.” I honestly don’t know where to even start. I’ve described diffusion and then gone on to narrate what happens when an organism has to breathe. I’m doing my A-levels. But I am seriously scraping an E. If it’s possible, would anyone be able to give me a laments version on diffusion? I don’t even know what guidelines I should be following, and what other points I should be branching out on? I’ve looked for information on the internet, on wikipedia and other sites. But everything is just a repeat of itself – …

For my online class I need to survey ten people on their answer to a question I make up about prohibition/legalizing of drugs. Any feedback is apprieciated! A short answer will do. 1. Should cigarette smoking be prohibited, restricted, or kept legal?

I almost feel stupid for asking for help on this one... I know I should be able to get it, but I'm feeling brain dead atm. Does this somehow involve MV=MV ?

Hello All: I am a student taking a Psychology course, and I have been given an internet research assignment. The assignment is as follows: 1. Contradictory definitions for the terms "theory" and "hypothesis" and/or contradictory explanations for the way the terms are used in conjunction with discussions about the scientific method. 2. Contradictory explanations of what is known as "the scientific method" or the process of research using "the scientific method". I am new to science and, although I am taking a science course as well, I could use a push in the right direction in dealing with this question. Can someone here help me figure this out? I really don't…

Hey could any of you guys help me and my groupmates with our science fair project? We are desperate, we need a topic that involves an experiment and not a demonstration, we would really appreaciate it. Thanks in advance to those who reply to our message, and to those who took the time to read it.

Mr Lam borrowed $3M from a bank to purchase an apartment. The bank offered him an interest rate of 4% and a payment period of 15 years. The monthly payment is $22191. Would you like to give me a calculator to find out whether the actual total payment? I wonder if it is = 22191*12*15

Could you please go to http://SciProj.yes2.us and participate in an experiment for my science project? Once there, you will click on a link to watch a 2-1/2 minute video. Then your browser will redirect you to a page with some questions for you to answer. After you participate, please do not post on this topic about the purpose or content of my experiment, as it will invalidate the results. Thank you! Matthew Rongey

I'm learning about nicotine, tobacco, etc but my assignments cannot be found in my book. I'll put my "guess" below every question because I did attempt every one of them. 1. The lungs' air sacs are destroyed, making breathing extremely difficult, in the condition called A. emphysema B. coronary heart disease C. chronic bronchitis D. lung cancer My guess: Emphysema.. But emphysema has to do with alveoli so I'm not sure. 2. Nicotine contributes to plaque buildup in blood vessels, increasing the chance of A. lung cancer B. diabetes C. hardening of the arteries D. oral cancer My guess: Increasing of blood vessels is caused by nicotine, whi…

As periodate may cut glucose into formic acids, how many cuts take place on a ring structure of glucose, and how many on the linear form of glucose? thank u for ur help!

If t2 = 17.00 s for slinky (a), what is t1?'' That is all the information I have to complete this question, and I dont really know where to begin. t1 and t2 seem to be .16 of a full wavelenght apart, and the amplitude is given, but I can't seem to get any more useful information out of there. Or alternately, I dont know what to do with the information I do have. Any help on this would be appreciated. I doubt its actually very hard, but I really need some help on starting off.

Just wondering...if you planned an experiment to compare the effects of two different types of exercise on aerobic fitness, which two types of exercise would you choose?

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I have a question that google could not answer for me. i was wondering what exactly is magnetism. i dont mean about doing experiments with iron fillings to see the magnetic field. I mean, what causes magnetism? what makes the atoms in all magnetic materials move towards magnets? I am halfway through my first year doing my GCSE's and would really like to know this. please help me if you can. G.B.