1. L

    Changes of gas in a vessel with a tap

    "A vessel of volume 2.0*10^-2 m^3 contains an ideal gas at a pressure of 1.50*10^5 Pa. A tap attached to the vessel is opened and the gas expands adiabatically until its pressure equals the atmospheric pressure of 1.01*10^5 Pa. The tap is then closed. The gas is allowed to return to its original...
  2. N

    Drinking bird temperature

    In a drinking bird, water from the wet on the outside of the head evaporates, causing the vapor inside the head of the bird to cool. This reduces the pressure of the vapor at the top, allowing the higher pressure in the lower bulb to push up the column of liquid. But the bird's body...
  3. L

    Temperature function of a gas derivation help

    I cant quite figure out how the so-called temperature function of a gas equation is derived from equations 1-4 in the attachment(from Planck's treatise on thermodynamics). Anything that helps me understand how this is arrived at would d be much appreciated!
  4. D

    Enthalpy formula

    Hi guys, I am relatively new in Thermodynamics as I am an electrical engineer. Right now, I am looking for an exact enthalpy calculation formula. The Gas is N2 with Temperature 27C and Pressure 124.73 bar. From a paper the enthalphy is 288.28 kJ/kg. I also found the same answer from online...
  5. E

    Calculate the time it takes for river gravel to take on the same temperature as the a

    Heres the scenario: Water level drops in a river. The previously saturated gravel slowly takes on the same temperature as the air. Assuming the gravel was originally the same temperature as the water, and the surface is flat, How long does it take? I believe these are the relevant formulas...
  6. S

    Calculate outlet temperature of adiabatic turbine

    Assume the gas is ideal and monatomic. The inlet gas is at 0.100 MPa and 25 degrees C. The outlet gas is at 2.0 MPa. The work rate is 10 kJ / mole of gas. I know that the work = delta h, so it's outlet enthalpy minus inlet enthalpy. I've tried using this formula for a reversible adiabatic...
  7. S

    Calculating Mixture Critical Temperature and Pressure using Equation of State?

    Hello Everyone, I am trying to calculate critical Temperature and Pressure of binary and ternary mixtures using equation of state. In particular, I am using Peng-Robinson Equation of State. I combined this with Van-der Waals critical criterion to get my result, but am way off experimental data...
  8. O

    The cable resistence constant with the temperature

    I am confused with this question, difficult to find steps to solve it. A carbon cable and a tungsten cables are connected each and made a cable. The resistivity of tungsten is 5.6*10^-8Ωm and carbon is 3.5*10^-5Ωm. The temperature coefficient of resistivity ,tungsten=0.0045°C-1 and...
  9. P


    The heat capacity of the interior of a refrigerator is 4.2 / kJ K . The minimum work that must be done to lower the internal temperature from 18 degree C to 17 degree C, when the outside temperature is 27 degree C will be
  10. H

    by what distance piston will move, if the temperature were increased by 57 deg?

    since it is ideal gas, I can use PV1/T1 = P2V2/T2 equation P is constant V2 = V1*T2/T1 T2 = 57 C --> 330 K T1 = 0 C --> 273 K the height, the width is the same only length changes so height*length*x = (height*length*0,1 m) (330/273) K x = 33/273 = 0,12 m = 12 cm P moves by 12 cm - 10 cm = 2...
  11. S

    Thermodynamics - Temperature change of argon gas

    the temperature of n = 19 mol of argon gas is increased from T1 = 21 oC by Q = 4.4 kJ heat transfer, while the gas pressure is kept constant. What is the new gas temperature in Celsius degrees? Q=n*Cv*change in Temp as its a monoatomic gas I think this means that the equation is just...
  12. T

    Magnetic flux density and temperature

    Hello everyone! I am new in the forum; and I am currently studying physics at the high school level. I have a little problem... and I would greatly appreciate any help that you could provide me; The thing is; I have to do an investigation on the relationship between magnetic flux density...
  13. Z

    Air refraction as function of TEMPERATURE

    I have been looking for a chart/function but couldnt find. I need it to do studies on a Schlieren set-up, which relies on the difference of density, thus variations of the air refraction, to make air flow visible. Hereby I attach a video that explains it better QpP4qM8wcNM So, I...
  14. F

    Diffusion equation

    Hello! I'm a physics student and i have a problem i can't solve. I was wondering if there is anyone here who would be willing to help me solve this? House: a room (see attachment) has perfectly isolated walls, except the two windows where a convective heat exchange takes place (with the...
  15. M

    calculate the temperature due to Power loss over a res.

    Hi All, Having the following problem I am trying to solve I am an electronics guy some of e physics eludes me in my calc. Here goes.... I am supplying 125Vac into a R which is a 20kohm resistor where I have a 12V zener in series to GND. P_loss = (125Vac - 5V)^2 / R P_loss = 0.72W So lets...
  16. avito009

    Can absolute zero temperature be reached?

    The third law of thermodynamics states: An absolute zero temperature cannot be reached. Temperature is a measurement of the average speed of the molecules of a substance. Try as we might, we cant get molecular motion to completely stop. So does that mean at absolute zero temperature the...
  17. W

    BlackHole-gravity or temperature

    Supposedly the gravitational pull of Black holes is so intense that not ever light can escape. Isn't this nonsense? The temperature of a BH is near absolute zero. At Zero there is no light being created or attempting to escape. So the blackness of a BH is due to temperature not gravity, correct?
  18. M

    Finding temperature before combustion

    Hi All, I'm completely stuck :( I've been trying to find the temperature of air in an otto cycle before the fuel is ignited. I know exhaust air is 733^C, Cp is 1005, air flow mass rate is 0.00460 fuel mass flow rate is 0.000393. The cal val for fuel is 46.5 Mj/kg, and im using...
  19. O

    Temperature Increase due the radiation absorption

    Hello Everyone, I am trying to understand how to calculate the temperature increase due to the absorption of radiant energy by an object that can be approximated by a blackbody (emissivity and absorptivity close to 1). As radiant energy is being absorbed, the body temperature increases until...
  20. K

    Curie temperature of intermetallic phase FeZn13

    Hi,hope someone in here can help me with my issue. I need to find out what is Curie temperature for intermetallic phase FeZn13. Is CT drastically lower or it will be near to the CT of pure Fe - 760 °C? It is hard to find out the particular information and maybe I could find out the solution by...