Per Definition and 565 Threads

Homework Statement Describe a method by which the charge / mass ratio e / m of the electron has been determined. Calculate the deflection sensitivity (deflection of spot in mm per volt potential difference) of a cathode ray tube from the following data: electrons are accelerated by a...

Homework Statement "An infnitely long hollow cylinder of radius ##a## has surface charge density ##σ_a##. It is surrounded by a coaxial hollow cylinder of radius ##b## with charge density ##σ_b##. The charge densities are such that the total confguration is electrically neutral. Using whatever...

Homework Statement frequency, Tension, mass, mode of vibration Homework Equations v = sqrt(T/μ) The Attempt at a Solution length of string is 2.14m weight .00247kg mass per unit length (μ) .00089 However, I need to confirm this graphically. I solved for mass per unit length μ = T/V^2 or...

What is the occurrence rate of planets? I'm not talking about earth-like planets, but any planet in general. I can't find a source that examines this number, all I can find is the average number of earth-like planets. Can anyone lead me to a useful paper/source? Thanks in advance

Homework Statement [/B]Quartz is positive uniaxial crystal with ne (extraordinary axis) = 1.553 and no (ordinary axis) = 1.554. A) determine the retardation per mm at lambda (wavelength) when the crystal is oriented such that retardation is maximized. B) At what thickness(es) does the...

Yeah, I can't seem to figure this out.. school sucks. If your car travels 260 miles and uses 8.2 gallons, how many miles per gallon did you get? (Round your answer to three decimal places.

Hi everyone, I was reading up on bit rate vs Baud speed, and sort of got myself straight with it, but I have a few questions.. First of all why isn't the term Baud still used? We see devices and speeds quoted at their bits per second speeds, but is this just by convention now, or is baud speed...

EDIT: I figured out what I'm stuck on is WHY do nuclear reactions favor the a reaction such that the product has a HIGHER binding energy per nucleon? Also how is energy released in a fusion reaction if the product requires more binding energy per nucleon? I need an explanation... "The graph...

The following derives the relation that for a blackbody radiation the energy density is proportional to the energy emitted per unit area over unit time. The average energy density ##d\psi## is obtained by dividing the radiant energy ##dE## received by the surface ##dB## in 1 second by the...

An allowed state of a molecule in a gas that is in a box of length L can be represented by a point in 3 dimensional K-space, and these points are uniformly distributed.In each direction points are separated by a distance π/L. A single point in K-space occupies a volume (π/L)^3. The number of...

Homework Statement The average wavelength that LED emits is 500nm. The electrical power of the LED is 300mW and the efficiency of turning energy into light is 66%. Number of emitted photons in unit time is? Homework Equations ##E_f=hcf## ##\frac{Pt}{E_f}=number of photons## The Attempt at a...

I am calculating damage per second (DPS) for a character in a video game. This character strikes twice every 4th attack. (Doublestrike) This extra strike does 50% of your attack damage. This extra strike, along with all other strikes, can crit, meaning meaning they do twice the damage. My...

Hello. The collisional frequency is generally expressed by ν = nt×average of (σv), where nt, σ and v are density of target (atoms or molecules), collisional cross section of target and kinetic velocity of incident particles. σ depends on kinetic energy of incident particles I thought...

Homework Statement During the game, the metabolism of basketball players often increases by as much as 30.0 W. How much perspiration must a player vaporize per hour to dissipate this extra thermal energy? Assume that perspiration is simply pure water and that perspiration starts at temperature...

This is probably a simple question A factory produce a good that requires 3 labor-hours in the assembly department and 1 labor-hour in the finishing department. Assembly personnel receive 19 per hour and finishing personnel receive 16 per hour. I need to write a matrix or vector product that...

Homework Statement A 15% by mass solution has a density of 1.2 g/mL. What is the mass per liter concentration of this solution? → (a) 180 g/L (this is the answer, pretend you don't know) (b) 150 g/L (c) 125 g/L (d) cannot be determined from this information Homework Equations Density...

Hello all! In my Nuclear Power assignment I decided to analyse this graph: I mention that "The difference in atomic mass and binding energy per nucleon for deuterium and helium (fusion elements) is ≈3u and 5.96 MeV respectively. However, for all elements past Iron (fission elements) the...

Homework Statement [/B] Determine the resistance of a conductor and the volt drop per ampere metre at 70°C for a 95 mm2 pvc/swa/pvc copper cable. The temperature coefficient of resistance is 0.004 per °C. Homework Equations [/B] R70 ( resistance at 70 degrees ) = R20 [ 1+( temperature...

Hello all,. I'm right now playing the publicly released data from the Illustris simulation. Im trying to plot the number of halos per logarithmic mass bin or the number of halos between mass M and M+dM I'm only familiar using theoretical models like Press-Schecter and I have no idea how do...

Calculate the head loss per metre length of a capillary tube which has a bore radius of 0.45 mm when a fluid of density 850 kg/m3 and viscosity of 25 cP is flowing at a rate of 50 l/hr. State whether the flow is turbulent or laminar. I have attached my attempt at a solution using poiseuille's...

Hey, I'm currently working a problem that looks like this: There's more to this problem, but I'm sure I can solve the rest of it, there are just things I'm uncertain about. Actually, it's only one thing I'm uncertain about. I'm looking through my notes, and when converting the voltage...

My Momma told me that if these humanoids can have up to 12 babies in a single pregnancy that they should have 8 teats like a dog does. However to me, having what is basically a single big breast with 8 teats seems weirder for a humanoid than the ability to grow a 3rd breast. I mean yes it would...

Homework Statement is the equation in the 3rd photo wrong ? since there are 2 exits , why shouldn't the eqaution become (P1 / y) + z + (8.33^2) / (2x9.81) = 0 + z +[ 2 (12^2) / (2x9.81) ] ? Homework EquationsThe Attempt at a Solution

Homework Statement A four cylinder, four stroke internal combustion engine has a bore of 3.7 in and a stroke of 3.4 in. The clearance volume is 16% of the cylinder volume at bottom dead center and the crankshaft rotates at 2400 RPM. The processes within each cylinder are modeled as an air...

Homework Statement An optical communication system operating at λ = 1550nm is transmitting pulses at 10 Gb/s. The magnitude of the optical pulses is the same. Calculate the number of photons received within each bit. Assume that the received average optical power is 10 mW. Homework...

Homework Statement why the author said the equation 3-4 as energy per unit weight ? as gamma = rho g , gamma has the unit of kg(m^-3)(ms^-2) = kg(m^-2)(s^-2) , gamma is clearly not weight ... Homework EquationsThe Attempt at a Solution

Hello. I've got two questions: 1) In the U.S., what's the average time per week that a graduate student doing a PhD in astronomy work? 2) In the U.S., what's the average time per week that a postdoctoral researcher in astronomy work? Thanks in advance for your answers.

Good evening, I'm an undergraduate astrophysics student currently doing research, and I wanted to get the opinion of some knowledgable chemists about a particular reaction my professor and I wish to emulate. Using a specific type of laser (Nd: YAG, for example), I'd like to mimic something...

Why would the speed of light happen to be 186282 mps? What is the property of light that settles on that speed. Why not 200000? Why not 154000? There must be some reason light doesn't travel any faster. And I don't mean relativity. If it was 200000 then Einstein and the rest of us would be...

Homework Statement I need to find the final impact speed of the flame of a non-uniform candle. I am given that the mass per unit length increases linearly from top to bottom starting with 1kg/m at the bottom and 10kg/m at the top. I need to find how fast the candle flame is moving once the...

Hey all, is there a formula that can calculate the energy losy by a photon traveling through air at 1 atm per meter given frequency? Any help apreciated.

Homework Statement (a) Calculate the energy of one photon of light emitted within the D-lines of a sodium lamp if the wavelength of the D-lines is 589 nm. (b) In a 200 W sodium street lamp, 30% of input electrical energy is emitted within the D-lines. How many photons of light are emitted...

Homework Statement A thin piece of metal foil of thickness 0.0700 mm separates one end of two pieces of optically flat glass. The top sheet of glass is 12.0 cm long. Light of wavelength 529 nm is normally incident on the glass. How many interference fringes are observed per cm in the reflected...

If you took: VBase / ZBase does that give you IActual or IBase or what? Because it seemed to give me IActual. Cheers

Homework Statement A ski gondola is connected to the top of a hill by a steel cable of length L and radius R . As the gondola comes to the end of its run, it bumps into the terminal and sends a wave pulse along the cable. It is observed that it took T seconds for the pulse to return. What is...

The classical definition of power is the rate of work per unit time, and the usual definition of work requires a mass to be displaced. However, power is alternatively stated as the rate of the transfer of energy. Now, suppose for example that one abstractly considers a light beam (without...

I am having the hardest time calculating q, the load per unit length. This question is in relation to my previous question I posted here. I have a cylinder laying horizontally that is fixed on its ends. The cylinder is filled with water. To calculate the deflection I am simplifying the problem...

Why do we use division/fractions to represent per something?

Hello Wizards! O.K. I know that 1 horsepower is generated by moving 300 lbs 100 feet in one minute. The question I seem unable to answer is... How many horsepower is generated by moving 19 lbs 1-1/2 inches in 1 second? Help please ( my brain is exploding ) Best Regards, Bill

Homework Statement A truncated cone has smaller radius of 5 feet, larger radius of 10 feet, and a depth of 1 foot. Total volume is approximately 183 cubic feet. If I have water in there at x inches how much does the radius at the surface of the water increase per inch? Homework Equations f(x)...

Homework Statement Is intensity related to this question? The answer is B. Homework Equations I^2 ∝ A^2 I=P/A, where I is intensity, P is power, and A is area The Attempt at a Solution I tried using I=P/A, and after substituting, I get, A^2=E/S, which gives E=A^2 S And then, the new wave...

Homework Statement Coaxial cable has double layered dielectric. a=2mm, b=4mm, c=8mm, εr1=3, εr2=4.5, Uab=1000V 1. Calculate capacitance per unit length of a cable. 2. Calculate inner and outer charge densities of a cable. 2. Homework Equations Gauss law C'=Q'/U σ = nD σp = nP 3. The Attempt...

Homework Statement Two cylindrical conductors, of distance between them d and radius a (a<<d), have dielectric layer of relative permitivitty εr and thickness a. Calculate capacitance per unit length of this system. Homework Equations Capacitance per unit length, C'=Q'/U Gauss law, cylindrical...

I am very bad at electrical applications. I would like to install 2 separate switches that can turn on and off a lamp. They are connected but located at 2 places. When one is switched on to turn on light, the other can also be used to turn it off later and vice versa. This is an extremely common...

In my base 10 math world there are rules for the gender of 1st generation numbers. They are: Primes alternate between 1 gender and another(specifically M and F) Composites have 3 more rules related to number of factors: M factors > F factors = M M factors < F factors = F M factors = F factors...

Hi, I'm trying to understand how Differentiation and integral works in practice, and would really appreciate some help interpreting this calculation- If we have a circle with Area A=pi*r^2 1) If i want to find the change in Area with respect to radius then dA/dr= 2pi*r2) If I'm told...

Several items are given fixed probabilities of selection per trial, one such item has a probability of 1.5%. What is the probability of selecting this item if 20 trials are permitted?This is not homework just a calculation for a game I play, so an explanation would be nice so I can do it myself...

So for sake of example the LHC beam one pointing at the other to cause a collision, the one beam is 6.5 TeV per beam. How can I calculate the volts per meter or given size of pulse? I understand that the particles have kinetic energy in the form of the speed of their travel but theoretically...

Homework Statement Ok so i know that the binding energy per nucleon inceases after fission and fusion and the difference in the binding energy is given out as energy. But if the binding enrgy increases shouldn't there be energy taken in(rather than given out)? Also why is the net loss in my =...

Hello! (Wave) According to my lecture notes: Suppose that we want to find the shortest path of a graph from $s$ to $v$ for some $s, v \in V$. - Subproblem dependency should be acyclic. #subproblems=$|V|$ time per subproblem: indegree $(v) $time= $\sum_{v \in V}$ indegree...