Mode Definition and 324 Threads

Homework Statement Derive the following result : \phi_k=-C_1(k)\frac{\dot{H}(t)}{H(t)} . Homework Equations \phi_k=C_1(k)\Bigg(1-\frac{H}{a}\int\limits^{t}a(t)dt\Bigg) a(t)= a(t_i)\exp\Bigg(H_i(t-t_i)+\dot{H}_i\frac{(t^2-t_i^2)}{2}\Bigg) The Attempt at a Solution So I stuck a(t) into...

1. hi there I am a bit confused, I am doing a survey of 100 respondents. ive asked them 5 colors to choose from ( red, green, blue, yellow and black) ive got these results from my survey of 100 respondents red = 21 green = 36 blue = 19 yellow = 10 black = 142. is my sample size 100? or 5? how...

Homework Statement Not homework but this seems the best place to post this. In a private conversation someone posted this explanation from a book on how a lamp filament fails.. I'm having some trouble doing the maths to show that the thinner higher resistance part gets hotter... Homework...

Hey guys, I am dealing with a slight issue here, I am learning the basics of class F amplifiers. but I am not able to understand that whether the transistor in class f operation works in linear mode or current control mode? Also i am dealing this problems at power levels of 10W to 25W scales, if...

Why HE11 mode of corrugated waveguides would not be a natural source of axion field?

Does activating flight mode help in reducing mobile radiation?

Hi All, I'm trying to understand the radiation mode of heat transfer. I have been reading the book by Incropera - "Fundamentals of heat and mass transfer" and have a few very basic questions. 1) Firstly, thermal radiation is the energy emitted by matter that is at non-zero temperature...

Hey all! I have been trying this problem for a while and can't seem to get the same answer as the solution. If someone can tell me where I am going wrong, that would be much appreciated. I am very close to the solution, but I am missing a term in the denominator. Everything is shown below! Thank...

Hello, I am building a prototype of a balance indicator to prevent farm quadbike to roll on steep hills. I am using an arduino pro mini and 2 sets of assignable strips of 8 leds (https://www.adafruit.com/products/1426) and a gyro-accelerometer sensor. To power it, I am using the farm motor bike...

Here's a problem I am doing right now. What are the cofactors " ## \Delta_{i \alpha} ##"? I know they are represent the minor of some determinant, but I am confused and can't see which determinant it is. Also, could somebody please help me and explain why ## ( V_{ij} - \omega^2 T_{ij} )...

Hi, I want to apply in Germany for MS in the area of switch mode power supplies design. Any good idea which university offer much courses in this area in English language... I want to apply in university where there is no tuition fee or a very minimum.

Hi, my level of knowledge of string theory is the following : I understand that to each elementary particle there corresponds a string vibrating at an associated frequency (mode). So my questions are : 1. Is there some table yet that proposes a correspondence? Such as : electron : so many Hz...

I've been reading a article about pulling a fiber (or actually making it thinner until it becomes single mode). As the fiber's diameter decreases, the transmission profile of the light is showing oscillations. The frequancy of these oscillations increases as the fiber is getting pulled. But I...

When buckling plate of both ends fixed, the deflection and the mode shape of the plate can be found from the equation: y=M(1-cos mx)/P. With this equation, the cross sectional area and the young's modulus of the plate is usually unchange. However, if the flexural rigidity of the plate is divided...

Hello What kind of lens (focal length and numerical apper.) i should choose to couple light ( wave length 1565nm, beam diameter 2mm, M-square>1) to a single mode fiber (core diameter 8 microns, mode field diameter 10 microns and NA=0.14)? Any thoughts Thank you

Hi guys, I posted a thread a while ago asking for advices to create a Finite Element model of a radioisotope thermoelectric generator. I've basically finished this model mainly using conduction and radiation at the boundaries. I am wondering something though: currently my heat gradient is very...

Hi I have a waveguide that is rectangular and multimode that I but-couple to a standard telecom SMF28 fiber. I have imaged the output of the waveguide and the fiber with a 25X microscope objective onto the chip of an IR-camera. Usually the mode overlap is calculated by cross-correlation of the...

Hi! I was wondering what happens with Base current direction if NPN BJT works in reverse active mode? In forward active and in saturation mode currents are like this: Collector and emitter currents in reverse active mode would be in opposite direction: :

Homework Statement It's a worksheet with questions like : A pelican flying along a horizontal path drops a fish from a height of 5.4 m. The fish travels 8.0 m horizontally before it hits the water below. What is the pelican's initial speed? Homework EquationsThe Attempt at a Solution [/B] So...

till now i used the normal method for finding out the mode of a given data that is just simply look for the most frequently occurring observation and label it as the mode. But recently I have encountered another method for finding out the mode in which it was also stated that my old method for...

Homework Statement I am trying to solve a problem from Jackson's book (in chapter 8). I must describe the propagation of a TEM mode through a transmission line that consists of two infinite conductor plates that are parallel to each other and separated by a distance a. There's a dielectric...

Homework Statement http://i59.tinypic.com/1smqlu.png I'm not sure how to calculate differential mode gain Homework Equations I know formuals for CMRR and Acm but not Adm CMRR = | Adm/Acm | Rb/Ra = (1-ε)Rd/Rc

I've started my trig class and this is the first time in my math career I've actually had to pay attention to what mode my calculator is in. So my question is, is there a rule for it? Will it be obvious to the problem?

Hi, Can anyone explain or point to a good introduction in simple terms the concept of 'light propagation mode'? I am in my final year at high school and need to write a research report on how optical fiber communication systems work. The report needs to include some contents beyond what is...

HI my dear friends i come back after few month absence:) is there anyone here who know how to determine motor mode or generator mode in ansys maxwell? i hope someone answer to this little question:) have nice time

Homework Statement Homework Equations [/B] The Attempt at a Solution [/B] Hello As you see my solution I found TM(5 , 2.5) that is incorrect because n should be integer not float number.In Addition when I check book solution I found TM mode is TM(2,1) what is my mistake?

I don't understand the condition of saturation in an npn transistor (common emitter config). My textbook says that the collector-emitter voltage reduces to near zero upon increasing input voltage. Also, Wikipedia says that both BE and CE junctions 'become' forward biased. Can anyone please...

Homework Statement A machine tool with mass ##m = 1000## kg and mass moment of inertia of ##J_0 = 300## kg-m##^2## where ##k_1 = 3000## N/mm and ##k_2 = 2000## N/mm which are located at ##\ell_1 = 0.5## m and ##\ell_2 = 0.8## m. Find the natural frequencies and mode shapes of the machine tool...

I trying to formulate a new project based on waveguides (~1 cm long) for sensing with the evanescent field. In all papers I've seen on similar topics they all aim for single mode (SM) waveguides, but I never understood the reason. Is there a quick answer?

What exactly is a mode and what exactly is a normal mode when talking about waves and oscillations? I keep looking on the internet but I can't really find anything concrete. Some definitions are very obscure.

Why we are not writing Cgs Cdb in depletion mode nmos here why no Csb in bottom nmos Can somebody please explain how to write which components of Cload or provide some links from where i can understand it better thank you, this picture is from...

What is the difference between complete and incomplete mode locking in charge density wave systems?

I am working with a single mode fiber at 830 nm with a NA of 0.12 (http://www.thorlabs.com/thorcat/19600/P3-830A-FC-2-AutoCADPDF.pdf). One end has a fiber tip coated in silver with a small hole of 200 nm diameter to essentially create a point source. My advisor told me that the fiber has a few...

Are these two, wave number and wave mode, same thing? If not, what is the difference? Thanks...

I have been working with equations throughout the semester and using them to find cutoff frequencies and such, but when you say something like TE10, TE20, TE21, etc., I am realizing that I am having trouble getting a physical idea of what exactly these things are. Of course if you transmit at a...

Homework Statement A cavity contains black body radiation at temperature T = 500 K. Consider an optical mode in the cavity with frequency ω=2.5x10^{13} Hz. Calculate a) the probability of finding 0 photons in the mode b) the probability of finding 1 photon in the mode c) the mean number...

Recently I am reading the papers in the field of PT symmetry systems. What I am confused is that in these papers, authors directly write out the equations describe the dynamics of the given systems( For example, in this paper http://arxiv.org/ftp/arxiv/papers/1103/1103.3389.pdf , authors put...

Hey all, Refer to page 5 in the pdf in the link (http://whites.sdsmt.edu/classes/ee481/notes/481Lecture26.pdf) I am having a little bit of a hard time understanding a portion of a derivation. You will notice that when determining the ABCD paramters of the shunt stubs they merely use A=1...

Homework Statement We are given that the transistor has β = 30. The BJT is shown below (along with the solution). Every value in the figure is given with the exception of the equation I circled in red: The Attempt at a Solution What I don't get is how they got the inequality Vc - Vb >...

Hi, Given the initial energy of a pion is it possible to calculate the probability and mode of its decay? Ive looked everywhere for a relevant formula but everywhere simply states the probability and mode... Wiki "The primary decay mode of a pion, with probability 0.999877, is a purely...

Why is it necessary for the gain magnitudes of inverting and non- inverting ends to be equal in magnitudes to be able to reject the common mode signal? Also can someone explain the ratio obtained of voltage divider in difference amplifier. R4/R4+R3[1+R2/R1]= R2/R1 Where, R1 input resistance...

magnitude of the "current" flowing around the nucleus in the Bohr mode Homework Statement According to the Bohr model, a hydrogen atom in its lowest energy state has a nucleus consisting of a single proton, which is orbited by a single electron. The speed of the electron is 2.19×106 m/s and...

How to find mode for grouped frequency distribution with unequal class length? I have to find the mode for the following problem: Marks No of students 0-20 32 20-50 45 50-70 15 70-100 8For equal class length, we use the formula Mode=...

Strange, and unique, at least to me. What is this mode? A slow data mode I guess. I've never heard it before. Anyone know what it is? Listen for the tones below the noise.. { URL removed by Mentor per OP's request }

Homework Statement Test scores are normally distributed. The mode of the score is 55%. If 75% of the students scored 65, what % of student scored 85? 2. Homework Equations and attempt at solution Scores being normally distributed, I know that as the 'bell curve (that means the curve is...

If T1 is in active mode all the time, will there be any current flow in this circuit? ( I think it is impossible to flow) thanks

Homework Statement The other day in lecture my professor mentioned the words mode locking and phase matching (same as velocity matching apparently) while on the topics of lasers. However, i can't find anything that can provide a simple explanation of what they are. Is there anyone who would...

I am working on a motorcycle dynamics problem. I have written the equations of motion in matrix form in MATLAB (and mathcad). It is a 4 degree of freedom system, so I have a mass, damping and stiffness matrix all 4X4. I am able to find from these matrices the natural frequencies, and damping...

Here we have question with answer Could please explain to me the answer of this question ? and can explain to me why we don't use area 2pi . r^2 because we have pipe ? and how we can know this combined modes ? I mean conduction and radiation ? In addtion , As I know s = the...

Electrical Engineering problems! Linear & switching mode power regulators: 1. What is the major weakness of a Buck Regulator that compared with a Linear Regulator? Is't efficiency? Passive harmonics filter: 1. If the filter reactance for harmonics is a negative value, what is...