Home >All Categories > Science & Mathematics >Physics >Open Question
V G Member since:18 April 2012Total points:51 (Level 1)Two bodies A and B have thermal
emissivities of 0.01 and 0.81 respectively. The
outer surface areas of the two bodies are the
same. The two bodies emit total radiant power at
the same rate. The wavelength ? B
corresponding to maximum spectral radiancy in
the radiation differs from that of A, by 1.00 µ m.
If the temperature of A is 5802 K,
A. the temperature of B
is 17406 K B. ? B = 1.5µ m
C. the temperature of B
is 11604 K
D. the temperature of B
is 2901 KAnswer QuestionBe the first to answer this question.
Tag Archives: Question
Open Question: What are the cells in your body that reject organ transplants?
What are the cells in *you’re* body that *regegt* organ transplants?
Now that we’ve got that amateur bit of grammar out of the way, we can move on.
To answer this question you must consider three points.
1. An organ is a church instrument.
2. An organ cannot fit inside a human.
3. You must be American.
This is not how surgery is performed in Britain, so I cannot help you here, sorry.
Gethin Watkins from Glyn-Neath
Open Question: M.S in Environmental Science and Engineering?
Hi,
I am working as a SAP EH&S consultant. I am intreste in doing M.S in Environmental Science. Please provide me the list of uniersities which offer this course as part time.
Cheers,
Vicky
Open Question: How can we derive h=2s\rpg. Where h= height s= surface tension r= radius p= density and g = acc.due gravity?
Open Question: how to find modulus of negative numbers?
x mod n where x<0
x mod n = (x + kn) mod n .. [Choosing k so kn > |x|]
so -17 mod 5 … [ Choose k=4 as 4*5 > |-17| ]
= (-17 + 4*5) mod 5
= 3 mod 5
= 3
Open Question: how to convert methyl bromide to toluene?
Open Question: Can I get few applications of heating effect of electric current in detail ?
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution.[1] Pure water is neutral, with a pH close to 7.0 at 25 °C (77 °F). Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. pH measurements are important in medicine, biology, chemistry, agriculture, forestry, food science, environmental science, oceanography, civil engineering and many other applications.
In a solution pH approximates but is not equal to p[H], the negative logarithm (base 10) of the molar concentration of dissolved hydronium ions (H3O+); a low pH indicates a high concentration of hydronium ions, while a high pH indicates a low concentration. This negative of the logarithm matches the number of places behind the decimal point, so, for example, 0.1 molar hydrochloric acid should be near pH 1 and 0.0001 molar HCl should be near pH 4 (the base 10 logarithms of 0.1 and 0.0001 being -1, and -4, respectively). Pure (de-ionized) water is neutral, and can be considered either a very weak acid or a very weak base, giving it a pH of 7 (at 25 °C (77 °F)), or 0.0000001 M H+.[2] The pH has no upper or lower limit and can be lower than 0 or higher than 14,[3] although with water, it is limited by the acidity and basicity of water. For an aqueous solution to have a higher pH, a base must be dissolved in it, which binds away many of these rare hydrogen ions. Hydrogen ions in water can be written simply as H+ or as hydronium (H3O+) or higher species (e.g., H9O4+) to account for solvation, but all describe the same entity. Most of the Earth’s freshwater bodies surface are slightly acidic due to the abundance and absorption of carbon dioxide;[4] in fact, for millennia in the past, most fresh water bodies have had a slightly acidic pH.
However, pH is not precisely p[H], but takes into account an activity factor. This represents the tendency of hydrogen ions to interact with other components of the solution, which affects among other things the electrical potential read using a pH meter. As a result, pH can be affected by the ionic strength of a solution—for example, the pH of a 0.05 M potassium hydrogen phthalate solution can vary by as much as 0.5 pH units as a function of added potassium chloride, even though the added salt is neither acidic nor basic.[5]
Hydrogen ion activity coefficients cannot be measured directly by any thermodynamically sound method, so they are based on theoretical calculations. Therefore, the pH scale is defined in practice as traceable to a set of standard solutions whose pH is established by international agreement.[6] Primary pH standard values are determined by the Harned cell, a hydrogen gas electrode, using the Bates–Guggenheim Convention.
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Open Question: WHICH IS THE IMPORTANT POINTS ON CHAPTER–CELL FOR CLASS 8….?
Open Question: where is the top three large bridge in world?
The Millau bridge in southern France would be a candidate for the number one spot.
see this article for a description:
http://en.wikipedia.org/wiki/Millau_Viaduct
It has a maximum height above the River Tarn of 343 meters.
Open Question: About DIPLOMA IN EMERGENCY MEDICINE (RCGP UK) FROM APOLLO ?
Home >All Categories > Science & Mathematics >Medicine >Open Question
happy Member since:09 June 2011Total points:220 (Level 1)can any indian or UK doc kindly tell me what is the scope of DEM from RCGP UK ?
Can one practice in UK after completing this ?
What exactly a Fellowship diploma means ? Which degree or diploma it is comparable to ? Is ther any contry that consider DEM candidates above a basic medical graduation ? (like MBBS in India)
Thanks in advanceAnswer Question
Open Question: How to find the direction of resultant vector?
Let the 20N vector be along x direction, so the 10N vector is along -x as they are 180deg apart.
10N vector on a +x scale would have magnitude of -10N in the +x dirn
So resultant would be the sum of them ie 20 + (-10) = 10 N in the direction of the 20N vector
Open Question: Determining the refractive index?
Home >All Categories > Science & Mathematics >Physics >Open Question
Sami Member since:03 May 2010Total points:0 (Level 1)Light has a wavelength of 475.6 nm and a frequency of 5.302×1014 Hz when travelling through a certain substance. What is the refractive index of the substance?
The refractive index:Answer QuestionBe the first to answer this question.
Open Question: Which colour is produced by burning flame?
Open Question: is (x^3 + 2a^3 – 3xa^2) divisible by (x – a)^2 ?
Open Question: What are the possible causes of frequent voltage fluctuation in a single phase electric circuit?
If your definition of frequent voltage fluction is the voltage having a positive peak and a negative peak every 1/60 or 1/50 of a sec. and going to zero between positive and negative peaks then that is normal.
For abnormal voltage fluctions here are three.
1. There is a bad connection upstream.
2. There is a shorting issue either upstream or downstream.
3. There is a problem in the power source.
These three items cover everything I can think of.
Open Question: which is the first “tree” or “seed”?
This question was originally intended to ‘ lose ones-self in meditation to the wonders of life’ But scientifically – the answer is tree (and here’s why).
The organisms we see today after millions of years of evolution are here because they evolved the function of reproduction. The seed is simply the trees method of reproducing (the seed itself cannot be the first because it is dormant until conditions are favorable).
However the tree is actively living so thus it is the latest of its species as it evolved from its ancestor species (who managed to reproduce through-out evolution).
Therefore the noteworthy question becomes – what was the tree before it was a tree (it was some other living organism capable or reproducing itself)
Open Question: what is the reverse bias resistance of the 0a79 diode at high Temperature?
Home >All Categories > Science & Mathematics >Engineering >Open Question
Siddhant Member since:11 January 2012Total points:139 (Level 1)I am using the diode 0a79 in a circuit called sensitive temperature switch
i have read that the reverse bias resistance of the diode 0a79 is about 10k at room temperature and as the temperature increases , the resistance of the diode suddenly falls down.
and this property is used for the switching action.
may i know at which temperature,the temperature will fall down?
or what is the highest temperature that i should apply at diode to check the circuit?
it would be better if i get the data sheet for the diode 0a79Answer Question
Open Question: one of my electrical motor burnt due to fan failure.Its fan is made up of plastic and how to overcome?
You need to find a motor rated at that ambient temperature.
Talk to motor manufacturers and get a quote.
Open Question: can overdose of disprin cause a death?
Open Question: I have two industrial servers one main and other standby,both of them are hanging frequently even though room?
Most servers will have error logs. Check them out. They are the starting point.
It depends on the OS and what are the jobs running on them.
OK
Open Question: what is the difference between total spin and “spin only” magnetic moment?
Basis for spin magnetic moments
A spin magnetic moment is induced by all charged particles. The electron is an example of one such charged particle. A spin magnetic moment is created because a particle has physical properties known as spin and electric charge. The spin within classical physics would be an object that rotates axially around its center of mass. In quantum mechanics, elementary particles are points, which have no axis to revolve around. This means these particles do not have spin in a classical sense, as angular momentum is defined by \mathbf{L} = \mathbf{r} \times \mathbf{p}, but have the physical property of angular momentum (see Spin (physics)). Maxwell’s theory of magnetic fields dictates that any moving charged particle creates a magnetic moment, and by definition, angular momentum designates movement. This is where the magnetic moment emerges in classical electromagnetism. See Maxwell’s equation
[edit] Calculation
We can calculate the observable spin magnetic moment (a vector), \vec{\mu}_S, for a sub-atomic particle with charge q, mass m, and spin angular momentum (also a vector), \vec{s}, via:
\vec{\mu}_S \ = \ -g \ \frac{q}{2 m} \ \vec{s}
(1)
where g is a dimensionless number, called the g-factor. This number depends on the particle: it is g=2.0023 for the electron, g=5.586 for the proton, and g=-3.826 for the neutron. The proton and neutron are composed of quarks, which have a non-zero charge and a spin of \hbar/2, and this must be taken into account when calculating their g-factors. Even though the neutron has a charge q = 0, its quarks give it a magnetic moment. The proton and electron’s spin magnetic moments can be calculated by simply setting q = e.
The intrinsic electron magnetic dipole moment is approximately equal to the Bohr magneton because g\approx 2 and the electron’s spin is also \hbar/2:
\mu_S\approx 2\frac{e}{2m_e}\frac{\hbar}
(2)
Eq. (2) is normally written as
\vec{\mu}_S = -g \mu_B \vec{s}
(3)
where µB is the Bohr magneton.
Just like the total spin angular momentum cannot be measured, neither can the total spin magnetic moment be measured. Equations (1) – (3) give the physical observable, that component of the magnetic moment measured along an axis, relative to or along the applied field direction. Conventionally, the z-axis is chosen but the observable values of the component of spin angular momentum along all three axes (assuming a Cartesian coordinate system) are each \pm \frac{\hbar}{2}. However, in order to obtain the magnitude of the total spin angular momentum, wave mechanical corrections dictate that \vec{s} be replaced by its eigenvalue, \sqrt{S(S+1)}. In turn, calculation of the magnitude of the total spin magnetic moment requires that Eq. (3) be replaced by:
|\vec{\mu}_S| = g \mu_B \sqrt{S(S+1)}
Thus, for a single electron, with spin quantum number s = \frac{1}{2}, the component of the magnetic moment along the field direction is, from Eq. (3), \vec{\mu}_{S,z} = \mu_B, or one BM, while the [magnitude of the] total spin magnetic moment is, from Eq. (4), |\vec{\mu}_S| = \sqrt3 \mu_B, or 1.73 BM.
The analysis is readily extended to the spin-only magnetic moment of an atom. For example, the total spin magnetic moment (sometimes referred to as the effective magnetic moment when the orbital moment contribution to the total magnetic moment is neglected) of a transition metal ion with a single d electron outside of closed shells (e.g. Ti3+) is 1.73 µB since S = 1/2, while an atom with two unpaired electrons (e.g. V3+) with S = 1 would have an effective magnetic moment of 2.83 µB.
[edit] Spin in chemistry
Spin magnetic moments create a basis for one of the most important principles in chemistry, the Pauli exclusion principle. This principle, first suggested by Wolfgang Pauli, governs most of modern-day chemistry. The theory plays further roles than just the explanations of doublets within electromagnetic spectrum. This additional quantum number, spin, became the basis for the modern standard model used today, which includes the use of Hund’s rules, and an explanation of beta decay.
[edit] History of spin magnetic moments
The idea of a spin angular momentum was first proposed in a 1925 publication by George Uhlenbeck and Samuel Goudsmit to explain hyperfine splitting in atomic spectra.[1] In 1928, Paul Dirac provided a rigorous theoretical foundation for the concept with his relativistic equation of motion for the wavefunction of the electron.[2]
Open Question: i want put fencing on my 1.24 acre of land with eight feet distance of stone pillor , how many pillors needed!?
assume that land is in square shape.
a^2 =1.24 acre
a^2 = 1.24x 4046.85 square meter
a^2 = 5018.094
a = v5018.094
a = 70.83 meter
so perimeter , 4a = 4×70.83 = 283.35 meter
we know 1 meter = 3.28 feet
so perimeter = 283.35×3.28 = 929.40 feet
since one pillar is 8 feet long,
total number of pillar required = 929.40/8 = 116.175
so approx 117 pillars are required.
Open Question: Three wires red,black and green in the plug of electrical food mixture.please help me..!!!!!?
What country is this?
The green wire is the ground connection. In the U.S. the other wires would be white and black with the white the neutral and black the hot.
Colors vary with country, but green or green-yellow is usually the ground connection.
Cut the plug off, buy a new one at a hardware store. Don’t try to repair the one you have.
Open Question: What happens to a eardrum when a sound wave enters the ear?
Open Question: is dead sea in canada? in which country is it in?
In Canada? Where’d you get that from?
No, the Dead Sea borders Jordan and Israel. So it’s in the middle east, in Asia.
Open Question: what kind of projects on birds can i do as a msc zoology student?
their biological names, habitat, origin of ornithology etc
their divisions are also to be included. the project will have wider significance if you do so. do so some work in the backyard and take photographs my yourself the effect that creates is more than any projects that u just copy and write
good luck 😀
Open Question: How can the electrical conductivity of barium be explained by its bonding structure?
Open Question: can factors be negative . if yes then while factorising positive numbers why dont we include their -ve factor.?
Any negative number x is equivalent to the product of -1 and the positive number -x.
The only products obtainable by powers of the -1 factors are -1 and 1.
This means that the negative factors aren’t really separate information. We factor numbers because their factorizations are useful; information about negative factors would be completely redundant and therefore not useful.
Open Question: different between cactus and money plant?
Open Question: Can I get THC out of my system in 3 weeks?
Home >All Categories > Science & Mathematics >Botany >Open Question
John Doe Member since:23 August 2011Total points:152 (Level 1)I got caught at the end of march and have to do a program to take 12 hours of class and get tested a couple times. My appointment to talk about the program is on wednesday, which doesn’t mean I have to sign up yet, just learn about it. I last smoked on sunday and am not planning on smoking again for a while. I do run multiple times a week and sweat a lot during each run. Probably 4 or 5 2 mile runs a week. Can I get it out of my system pretty quickly if I drink a lot of water and keep running?I smoked pretty often before sunday, like once a day or once every other day. probably like 4 or 5 times a week.11 hours agoAnswer Question
Open Question: how to protect opening of series connected batteries when one of the cell is damaged?
Open Question: Interfacing and C code of at89s52 or atmega16 with stepper motor?
Home >All Categories > Science & Mathematics >Engineering >Open Question
Abhishek Member since:18 January 2010Total points:423 (Level 2)I am making a short range radar that just detects the presence of an object in the range of radar.I need help in interfacing unipolar srepper motor to either 8051(at89s52) or atmega16 controller using ULN2003 A . If you can provide a C code for that, it would be even better!thanks in advanceAnswer QuestionBe the first to answer this question.
Open Question: Problem understanding domain and co domain in functions?
Hi friends,
I have some problems in maths for which I am not understanding the domain and the co domain.
a. Let A, B, C is a subset of R square. where A = { (x,y) , y=2x+1}
B = {(x,y) / y=3x}
C = {(x,y) / x-y = 7}
here in the above question what does it mean by saying “A, B, C is a subset of R square”. I do not understand the significance of R square here.
Please let me know.
Regards,
Pradeep
Open Question: how to distinguish between ethyl chloride and benzyl chloride?
Open Question: college life at bits pilani vs vellore institute of technology?
can anyone tell me what the college life at the above mentioned colleges is like?
what activities are conducted?what are the people like? any alumni there please help me!
any pictures of ur college life wud be great!
Open Question: Cold Liq/ice can maintain for some time inside the land(ground) why is it so?
Home >All Categories > Science & Mathematics >Earth Sciences & Geology >Open Question
Minjesh Member since:25 September 2011Total points:90 (Level 1)If you have heard that in long ago there is no refrigerator. nowadays also in villages.cold substances,milk items,curd are kept under the ground(Land).so it’s temp can maintain for long time.is there any thermal properties of land or what.i have to give a assignment on this.if anyone find any details give a try to answer and link will be OK.help will be appreciated.Answer Question
by darkflow… Member since:14 December 2006Total points:4,701 (Level 4)Heat is passed in 3 ways: conduction, convection, and radiation. Underneath the ground the sun can’t reach items (no radiation). Air is not circulating underground (no convection). The only heat source available is conduction, or heat passed through solid material. This reduced amount of heat source, keeps the heat low.
Open Question: in which part of alimentary canal peristaltic movement does not take place?
Open Question: how much Natural Gas Required to got temperature 1000 degree Celsius?
Home >All Categories > Science & Mathematics >Engineering >Open Question
Pawan Member since:21 April 2012Total points:95 (Level 1)hello,
we in ceramic industry we fired sand with moisture less than 1% in kiln. we use natural gas to fire sand. i want to ask how much natural gas required to to got temperature of 1000 degree in kiln, if the sand weight is 20 kg. the gcv value of gas is 9880/scm. kindly tell how to calculate it. if there any formula.Answer Question
Open Question: Is there any entrance exam for aeronautical engineering in manipal?
Home >All Categories > Science & Mathematics >Engineering >Open Question
Sougat Member since:21 September 2010Total points:395 (Level 2)is there any entrance exam needed to be given for admission in aeronautical or aerospace engineering in manipal and what is the cut off and what are the deadlines for admission in 2012
i checked manipal.edu site but couldnt found anything about any entrance exam.Answer Question
by Kushi Albert Member since:20 April 2012Total points:155 (Level 1)papi..i guess there r no entrance exams.u can only enter through direct admission.fees considerations are given based on marks..
Open Question: calculate the no. of moles left after removing 10^21 molecules from 200mg of CO2?
moles = mass / molecular weight
Here we are told that the initial mass, m1, is 200 mg (or 0.2 g). And we can find the molecular weight of CO2 on wikipedia (or similar) – this is 44.01 g/mole (according to wikipedia). Therefore:
n1 = initial number of moles = 0.2 g / 44.01 g/mole = 0.0045 moles
Now we are removing 10^21 molecules from this. This number, expressed in units of moles, can be calculated from the following:
# molecules / # molecules per mole = # moles
Note: # molecules per mole = Avogadro’s number = 6.02*10^23 molecules/mole
Therefore:
(10^21 molecules) / (6.02*10^23 molecules/mole) = 0.0017 (this is the number of moles we are removing).
Therefore:
Number of moles remaining = initial number of moles (n1) – number of moles removed
Number of moles remaining = 0.0045 moles – 0.0017 moles
Number of moles remaining = 0.0028 or 2.8 E-3 moles
Hope this helps!
Open Question: What is the classification of amino acid on the basis of structure?
Open Question: Chemical Reactions in Diamond Industry?
Open Question: M.S in Environmental Engineering?
Hi,
I am currently working in SAP EH&S(Environment, Health & Safety). Could anyone please tell me the list of universities which offer post graduation courses.
Cheers,
Vicky
Open Question: What is the no. of electron in 1.8 ml of H2O (l)?
Home >All Categories > Science & Mathematics >Chemistry >Open Question
by Chris Hardy Member since:29 March 2012Total points:95 (Level 1)yaar its simple.. density of h2o isn’t given … so consider it to be 1.. so 1.8 ml =1.8gm
now we know that 1mole H2O = 18gm.. 1.8 gm = .1 mole.. now we know that there are 10 electrons in 1 H2O molecule hence in 1.8 ml its = 6.023*10^23*.1*10= 6.023*10^23 electrons….
Open Question: problem on proposition logic?
Hoe to solve the below problem:
An magazine states, “If I’m not watching movies, I’m
playing cricket. And if I’m not playing cricket, I’m listening to music.” We can
assume that the speaker cannot do more than one of these activities at a time. What
is the speaker doing?(Translate the given sentences into formal language; consider
the possible truth assignments.)
Open Question: why are most of the inner transistion elements tripositive ions?
The f-block of the periodic table of the elements consists of those elements whose atoms or ions have valence electrons in f-orbitals. Actual electronic configurations may be slightly different from what is predicted by the Aufbau principle. The elements are also known as inner transition elements, although that term is normally taken to include lutetium and lawrencium as well, which are part of the d-block.[not verified in body]
f-block * Lanthanoids 57
La 58
Ce 59
Pr 60
Nd 61
Pm 62
Sm 63
Eu 64
Gd 65
Tb 66
Dy 67
Ho 68
Er 69
Tm 70
Yb
Atomic electron configuration 5d1 4f15d1 4f3 4f4 4f5 4f6 4f7 4f75d1 4f9 4f10 4f11 4f12 4f13 4f14
Electrons per shell 2, 8, 18,
18, 9,
2 2, 8, 18,
19, 9,
2 2, 8, 18,
21, 8,
2 2, 8, 18,
22, 8,
2 2, 8, 18,
23, 8,
2 2, 8, 18,
24, 8,
2 2, 8, 18,
25, 8,
2 2, 8, 18,
25, 9,
2 2, 8, 18,
27, 8,
2 2, 8, 18,
28, 8,
2 2, 8, 18,
29, 8,
2 2, 8, 18,
30, 8,
2 2, 8, 18,
31, 8,
2 2, 8, 18,
32, 8,
2
** Actinoids 89
Ac 90
Th 91
Pa 92
U 93
Np 94
Pu 95
Am 96
Cm 97
Bk 98
Cf 99
Es 100
Fm 101
Md 102
No
Atomic electron configuration 6d1 6d2 5f26d1or
5f16d2 5f36d1 5f46d1or
5f5 5f6 5f7 5f76d1 5f9
or 5f86d1 5f10 5f11 5f12 5f13 5f14
Electrons per shell 2, 8, 18, 32,
18, 9,
2 2, 8, 18, 32,
18, 10,
2 2, 8, 18, 32,
20, 9,
2 2, 8, 18, 32,
21, 9,
2 2, 8, 18, 32,
22, 9,
2 2, 8, 18, 32,
24, 8,
2 2, 8, 18, 32,
25, 8,
2 2, 8, 18, 32,
25, 9,
2 2, 8, 18, 32,
27, 8,
2 2, 8, 18, 32,
28, 8,
2 2, 8, 18, 32,
29, 8,
2 2, 8, 18, 32,
30, 8,
2 2, 8, 18, 32,
31, 8,
2 2, 8, 18, 32,
32, 8,
2
All elements in the lanthanide series form M3+ ions. In aqueous solution the early lanthanides are surrounded by nine water molecules while the later lanthanides have a coordination number of 8. Cerium also forms compounds with the +4 oxidation state; Ce4+ has the very stable electronic configuration of the noble gas xenon and is a strong oxidising agent. Eu2+ has the configuration [Xe]4f7 and is a strong reducing agent. The existence of Eu(II) is attributed to the stability of the half-filled f-shell.[1]
Open Question: Name an angiosperm plant which neither fruit nor flower?
All angiosperms produce flowers and fruit, although some might not be things you would see as flowers or fruit unless you are a botanist.
Grass flowers and produces their fruit a botanist calls a caryopsis and most people call grain.
Wind pollinated trees have catkins or similarly nonflower-like inflorescences. Alders (Ulnus spp) have female ‘cones’ and tassel-like male catkins as their inflorescences. These are flowers as they have an enclosed ovary protecting the female ovule.
Maple tree fruit are the bladed samaras that twirl and glide through the air.
http://faculty.fmcc.suny.edu/mcdarby/animals&plantsbook/Plants/05-Angiosperms.htm#seeds,%20fruits,%20etc
Cottonwood poplars (Populus deltoides) produce the white fluff that bears the fruit away with the wind. http://www.cas.vanderbilt.edu/bioimages/species/pode3.htm#Flower
Open Question: If a particle is rotating between two magnetic fields, with certain velocity, this velocity depends upon?
Im not sure.. but may be due to magnetic filed..
🙂
Sorry, I could not read the content fromt this page.
Open Question: A doubt on work done?
I read in a text book that when a man is carrying load on his head and moving forward does no work since force acting at right angle to displacement and cos 90=0.
But the load is moving along with the man throughout,if it does so then there must be some force acting on the load which make the load move along with man.
If no force was acting tangentially then the load should have fallen down as he moved forward.
Hence there is a tangential force acting on the load and hence he has done some work.
What is wrong with my argument?
OMICS 