Per Definition and 545 Threads

I find David Deutsch to be interesting, however I find his writing style a little hard to follow at times. If anyone can shed light on what he means by the following, it would be appreciated: "the multiverse is not a discrete set of universes but a continuum" I can accept the concept of a...

Homework Statement For one of my assignments I’ve been ask about the relationship between percent impedance and per unit impedance. Homework EquationsThe Attempt at a Solution I know that the x% is determined in transformers by short circuiting the secondary windings and slowly increasing the...

Why is solar spectral intensity per wavelength different than solar spectral intensity per frequency?

Hi, my name is alexander, i am student from Institute of radioprotection and dosimetry (IRD). My project is calculate MGD (mean glandular dose) from womans with augmented breast. i am having dificulties to calculate Kerma in air with mcnpx. I drew a block of air above the breast, i am using the...

Homework Statement Compare resonance energy per ring in benzene, napthalene and anthracene Homework Equations -- The Attempt at a Solution I know Resonance energy of benzene is 36 KCal/mol, I also know anthracene is the most stable followed by napthalene so their resonance energy is in the...

Homework Statement We are investigating hydrogen in a plasma with the temperature 4500 ºC. Calculate the probability per atom and second for stimulated emission from 2p to 1s if the lifetime of 2p is 1.6 ns Homework Equations Planks radiation law: ##\rho (f) = \frac{8* \pi...

Homework Statement We are investigating hydrogen in a plasma with the temperature 4500 ºC. Calculate the probability per atom and second for stimulated emission from 2p to 1s if the lifetime of 2p is 1.6 ns Homework Equations ##A=\frac{1}{\Sigma \tau}## $$A_{2,1} = \frac{8*\pi *h *...

Can anyone find an actual paper? I cannot. This is an un-refereed citation, more like a slide show for a talk: "Dissolving the Fermi Paradox" Anders Sandberg, Eric Drexler, Tony Ord...

Hi all Trying to improve my level of maths and would like some help with the below question please. A 10-year lease with annual rental payments to be made at the end of each year, with the rent increasing by 2% each year. If the first year rent is £20 and the OCC is 10% per year, what is the...

Hello everyone, I'm a high school student, currently in 10th grade. I'm going to major in physics, I'm interested in how many hours should I study physics and maths per day to do my best and to be as smart as possible? I don't only want to master high school materials, I also want to learn...

Homework Statement Homework EquationsThe Attempt at a Solution I know the units for V is J/C so #3 and #4 are wrong. But how do I determine the signs?

<< Mentor Note -- poster reminded to use the standard Template >> Question Three A pipe of outside diameter 200 mm is lagged with an insulating material of thermal conductivity 0.06 W m-1 K-1 and thickness 75 mm. The pipe carries a process fluid at a temperature of 300 °C and the average...

Hi, I'm currently stuck on a homework question and I was hoping if I could get some help. Group A has 50% chance of ordering french fries (price: 5),40%chanceoforderingmilkshake(price:6), and 10% chance of ordering a burger (price: 7).GroupBhas30%chanceoforderingfrenchfries(price:5), 30% of...

A friend and I have reached a disagreement, and truly neither of us can come up with the math to prove one of us right or wrong. So I pose the question in here for someone to offer me a proof of which theory is correct. The question is about what is the proper way to calculate damage per...

I recently watched a great video demonstrating the floating water bridge experiment: At around 34 sec, you can see an electrostatic discharge before the water bridge forms. I've read that this is due to the electrostatic breakdown of air between the two beakers.This made me curious about the...

Homework Statement Homework EquationsThe Attempt at a Solution ## dS = \frac { dQ_{rev} } { T } ## Assuming that isothermal process is a reversible processes, ## dU = dQ – pdV## For isothermal process, dU = 0. ## dQ = pdV ## ## pV = nRT##, where n is number of moles. For one mole, ##...

Homework Statement Homework EquationsThe Attempt at a Solution [/B] I am taking the free energy as the internal energy of the ideal gas. Then the average internal energy per unit volume is ## \frac { 3 nk_B T } {2 } ##. So, the correct option is (c). Is this correct?

Homework Statement [/B] A fuel gas consists of 75% butane (C4H10), 10% propane (C3H8) and 15% butene (C4H8) by volume. It is to be fed to the combustion chamber in 10% excess air at 25°C, where it is completely burnt to carbon dioxide and water. The flue gases produced are to be used to...

$\text{$32$}$ $\text{Newmarket Industries currently has $2,000$ shares of common stock outstanding. }$ $\text{The Firm has assets of $\$200,000$ and total liabilities including preferred stock of $\$75.000$.}$ $\text{Calculate the book value per share of Newmarket common stock}$...

in question 10.19 , i use equation 10.26 to do the question . I have all the values of all variables , except q ( load per unit area) ... Homework EquationsThe Attempt at a Solution How to get q ? It's not stated in the textbook . Is there something to do with the homework =4m ?? I assume q =...

What is the average power consumption in watts of an appliance that uses 6.65 kW*h of per day? 6650/24=277 W b) How many joules of energy does this appliance consume in a year? What is the conversion factors for b)?

Homework Statement A centrifuge is a device in which a small container of material is rotated at a high speed on a circular path. Such a device is used in medical laboratories, for instance, to cause the more dense red blood cells to settle through the less dense blood serum and collect at the...

What are the factors which determines how many bytes / kilobytes / gigabytes of data a computer can process every second? Are there any equations / formula / rules that can be used to work this out.

I would like to find the 12 to 19 abortion rate per 10,000 women from the following table: This would be the merging of age groups "12-17" with "18-19" to some how get the 12-19 abortion rate. EDIT: "Distribution of abortion age" was translated from "Répartition des ges l'avortement" in...

Homework Statement A group can charter a particular aircraft at a fixed total cost. If 36 people charter the aircraft rather than 40 people, then the cost per person is greater by 12$ a) What is the fixed total cost to charter the aircraft? b) What is the cost per person if 40 people charter...

I'm a civil/structural engineer and I was just recently thinking about one of the biggest issues for maximizing the efficiency of a wind turbine - the structure itself. The mega turbines that engineers want already have foundations of titanic proportions because as we all know, flag pole...

Hello, Can anyone explain the procedure to convert mg/s to SCCM? I'm working with an Alicat Mass Flow Controller, which regulates Argon (Ar) mass flow from 1 to 6 mg/s at 27o C or 300 K (room temperature). For documentation purpose, I need mass flow in terms of mg/s, as well as, SCCM. Thank...

Homework Statement What is the ratio of the amount of Vitamin C in 500 grams of orange to the amount of Vitamin C in 500 grams of orange juice? There is a graph associated with this question which is attached. I can't find out the amount of Vitamin C in 500 grams because the data is given...

Tickets at a fair cost 75 cents each. You can also buy a roll of 25 tickets for 15 dollars. What is the total cost of each ticket if you buy a roll of tickets? Is this a proportion problem? Do I divide 25 by 0.75 to find the total price for each ticket?

Homework Statement A fireman's hose acting as a water cannon, directs 100 litres/s (100 kg/s) of water horizontally at your chest at speed 5 ms-1. Assuming water essentially falls to the ground after hitting your chest (rather than say reflecting horizontally backwards), what horizontal force...

Homework Statement (a)Estimate the number of photons per second emitted by a 100-W lightbulb, assuming a photon wavelength of 550nm.(b) A person can just see this bulb for a distance of 800m, with the pupil dilated to 7.5mm. How many photons per second are entering the pupil? Homework...

Homework Statement The equation of state of an ideal gas is p = nkT, where p is the thermodynamic pressure and n = N / V is the thermodynamic variable for the number of particles per unit volume. The n dependence of the free energy f per unit volume of the ideal gas is obtained by the following...

Ok so essentially in this video game I have there are certain stats on swords. The stats are the amount of Attack animations, amount of time to compleate all of the attack animations, sword dammage and critical chance. All of the animations deal the same amount of dammage and the time to...

First I am not sure if this is the correct place to post this thread, but the thread will be about optics, quantum physics and special relativity, so it is a mixed subject. Please watch this video first: This technology allows capturing videos at mind blowing 1 trillion fps, which allows us...

Homework Statement A fuel gas consists of 75% butane (C4H10), 10% propane (C3H8) and 15% butene (C4H8) by volume. It is to be fed to the combustion chamber in 10% excess air at 25ºC, where it is completely burnt to carbon dioxide and water. The flue gases produced are to be used to generate 5...

Homework Statement Suppose a harp string is tuned to middle C (C4) and is 0.56m long. If I want the tension to be 193.5 N, what mass per unit length do I need the harp string to be? Calculate your answer in kg.m Homework Equations Vs = sqrt(T/μ) V = fλ The Attempt at a Solution Having a very...

Homework Statement Calculating the rms speed of an N2 molecule. The units I end up with are J/kg and this is equivalent to Velocity. my question is why? Homework Equations v = J / kg KE = .5mv^2 The Attempt at a Solution I tried to derive it myself using the kinetic energy formula. What I end...

In my labs we use hot plates with a 0-10 temperature knob. The hot plates don't have a temperature monitor, so i have no idea how hot each number can increase it or how hot it is at the time. Sometimes i have labs where i have to heat something to more specific temperatures or else the reaction...

Homework Statement An arrangement of four wires, in cross section, with θ=30° and u=5cm. Wire 2 and wire 4 carry the same magnitude of current (I2=I4=10mA) directed out of the page. Wire 3 carries current I3=25mA directed into the page. If the resultant force per unit length on wire 1 is zero...

1. Homework Statement An air coaxial transmission line has a solid inner conductor of radius a and a very thin outer conductor of inner radius b. Determine the inductance per unit length of the line. Homework Equations the book states the methodology to find the inductance as follows: 1)...

Using Optical Computing, what is the max amount of state changes that 1 transistor could theoretically have within 1 second? I once read that an electrical transistor could achieve 100 billion state changes per second, but I'm wondering what the number is for light, *and what it could...

Triangle Construction pays Square Insurance 5980 dollars to insure a construction site for 92 days. To extend the insurance beyond the 92 days costs $97 per day. At the end of this period, if Triangle extends the insurance by 1 day, how much more does Triangle pay for that day than it paid per...

I designed this game for my Data class but I'm having a lot of trouble calculating the expected profit per play of this game. We have taken up examples involving lottery tickets in which you have to calculate the profit and winning per ticket bought but I can't seem to apply the same concepts to...

Homework Statement Three long straight parallell wires that conduct electricity called L1, L2 and L3. The angle at L2 is 90 degrees and the distance between L2 and L1, L3 is 0,50 meters. The current through the wires L1 and L3 is 300 A while the current in L2 is 600 A. Decide the resulting...

1.Recently, we performed an experiment to measure the efficiency of the Stirling Engine. The experimental method can be seen in the image provided. We have been asked to calculate the power dissipation PR and the energy dissipation per cycle WR as part of our lab report. The other variables...

There is this bike manufactured in India with a 180CC single cylinder petrol engine with Twin Spark plugs. They highly market their "twin spark technology". Well according to my knowledge, I don't think that will make much difference in performance and efficiency. What do you think? Is this just...

Homework Statement The beam of electrons in a cathode ray tube contains electrons traveling at 8.4x106 ms-1 and the current throgh the tube is 2.8 micro A. a) how many electrons are emitted per second from the cathode of the tube b) what is the number of electrons per unit length of the beam...

Homework Statement When iron is irradiated with neutrons an isotope of iron is formed. This isotope is radioactive with a half-value period (half-life) of 45 days. Give the meanings of the terms printed in italics. A steel piston ring of mass 16 g was irradiated with neutrons until its...

How would you calculate the concentration of a vapor above a liquid in a sealed jar in parts per million? Supposing that the liquid is a 10% solution of X with known vapor pressure. We've gotten to this point: 1ppm = 1mgX/ g solution 1ppm = 1mgX/1mL solution (assuming it's water and water has...

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...