Heating Definition and 616 Threads

Suppose the temperature in your room is 25 °C with 100% humidity. You are feeling very hot and sweating a lot. Most of the sweat does not evaporate on your body, it just drips onto the ground. If you switch on the heating in your room, would you feel more comnfortable? It seems to me that by...

Hi! In a book it said that it can be clearly seen from the interatomic potential (such as the Lennard Jones) that when a solid is heated it expands. Please explain how is it exactly manifested by the interatomic potential graph?

COMSOL RF module: urgent Hi i am a new user to comsol RF module. Actually I a want to model the heating of a material using IR waves... can i use the RF module (which illustrates microwave heating as an example) to model the IR heating...do we have options to change the frequency of wave from...

Homework Statement F = Fahrenheit A particular temperature control system uses electrical heaters, exterior thermal insulation and a thermostat for maintaining the temperature at 170 F +/- 1 F. The thermostat turns the heater on when the temperature drops to 169 F and on at 171 F. Heater...

Ok so my question is about hot water in a home Lets say that I take a shower a shower and i use 20 gallons of water at 105* F If the hot water in my tank is at 140*F and my cold water comes in at 50*F how much of hot (140*F) water did i use? How much cold (50*F) Water did i use? Now...

Homework Statement A thin square tungsten foil, 10mm x 10mm, is supported in the centre of a vacuum chamber by thin wires which have negligible thermal conductance. A cooled shield surrounds the foil such that its initial temperature is -37 C. Two parallel slits, 1\mum wide and 1mm long...

Why are the heat coefficients for constant pressure and constant volume different? What is the physical reason?

Let's say there is a water based heating device that has 3/4" connection nipples. The pipe that leads to the device is 5/4". If one ignores pressure- and head loss, does it make any difference how far from the device the pipe reduces from 5/4" to 3/4" ?

Bit Stumped at the moment... I am attempting to design a system to take advantage of the solar energy available this summer, but am struggle to get the equation correct. Broken down, i have an aluminium pipe with water running thorugh it, which will gain energy from solar radiation, but...

Hi PF, I watched a video on youtube about a physics professor who asked some questions at the end of the video but didn't answer them. One really interested me. If you have a plane aluminum plate with a very little hole say in its center and you heat the whole plate. What happens to the size...

energy heating a home? Homework Statement During 2 hours one winter afternoon, when the outside temperature was 4° C, a house heated by electricity was kept at 20° C with the expenditure of 42 kwh (kilowatt·hours) of electric energy. (a) What was the average energy leakage in joules per...

I remember reading before that hydrogen gas is "transparent" to gamma rays. What does this mean? I know it has something to do with the gamma rays not heating the hydrogen. Also, would Xenon gas be transparent to gamma rays?

Hello. I'm planning on building a green house in my garden with a wind powered heating element to help sustain higher temperatures. I live in a windy area (North Sotland) so wind prevolance is no problem. Would an element be the best way to this or are there better methods of converting...

Just a question about heating compressed air.. I know generally how hot air works.. You heat it and particles expand and creates lift. So my question is, Does heating compressed air provide any lift? if so how much in relation to normal air? eg if I had 100m^3 of air heated to 120C...

I work for a contractor and we're currently discussing drains on the roof of a building, and whether they should have electric cable heating around them. It gets cold here and snow does accumulate on the roof. Under what circumstances should cables be used and not? Pros / cons?

I have read that some Scientists do not believe that the emissions from industry, power stations, transportation etc is the ultimate cause for a global warming scenario & they can't put there finger on another cause. Of course science is the study of what we don't know rather than what we do...

Hi Heat generated by the conductor because of DC is i*i*R where i is the current and R is the resistance. Does anybody know the heat generated by the same conductor for an AC? For example frequency 5kHz, DC resistance-20 ohms, RMS current is 3A.. How do we calculate this? I do not...

can someone help me please. Aluminum can with radius 12cm and height 25 cm, with walls 2 mm thick. We want to heat the center of the can to 74 C. 1) How long will this take using steam at 120 C and 140 kPa? Starting temperature is 25 C. 2.) How do I get heating profile at...

Hi I am living in a 2 bedroom house with base bord heaters but i have also purchesed 3 oil space heaters, my landlord since has givin me a bogus eviction notice because of to much humididiy in the air, his fault really for nothin ensuring propor ventalation when repairing the house but my...

Is the corona heating problem with only Sun? Or all stars having this problem? i.e. outer layer of all stars have high temperature than its immediate inner layer?

I want to make a heated steering wheel for my car using hand warmers from a snowmobile. The power source is 12 VDC and the resistance is 10.0 ohms using 25 watts on the low setting and 19.6 ohms using 35 watts on high. That is for one handwarmer, I figure I will need about 20 of them. Will...

Homework Statement A 2.5kW electric kettle takes 3 mins to raise the temperature of 1.2kg of water from a temperature of 20 degrees C to a temperature of 100 degress. The specific heat capacity of water is 4.2kJ/(kg K) Homework Equations So far I know that we're either using P=vit ot...

Let's say it is 20 degrees Fahrenheit outside. If I have my thermostat set at 60 F, then each time my house dips below that temperature, my furnace should kick on and reheat it to 60 F. And the cycle continues... If I have my thermostat set at 68 F, then the scenario remains the same...

how to not short circuit an induction heating coil Just wondering about induction heating coils and how to not short circuit one. basically, if i hook up one end of the coil to the positive and one end to the negative (DC) i assume that i will be short circuiting the connection and also...

Hello, I have a question on rf heating in Paul trap. There are papers which say that in a Paul trap, the ion cloud eventually comes to a state of thermal equilibrium with the background gas. And at the same time there is a concept of "rf heating" in these traps. I am slightly confused about...

Hi all! I've been thinking of something lately. When an atom absorbs an incoming photon, the atom must gain some momentum in order to conserve linear momentum, right? Sort of like a totally inelastic collision? This momentum corresponds to some amount of kinetic energy and thus a raise in...

if i was to heat a gas [any gas] by 10 degrees celcius, using the smallest amount of heat energy, would i be better off heating the gas at constant pressure or constant volume. i think constant pressure, however i don't know how to justify my answer...:confused: cheers

i have set up an equation to get the heat transfer rate Q for a combined system where heat is transferred from a cylindrical outer wall set at 500 C. the wall heats a gas, which in turn heats a solid block of cylindrical metal positioned in the centre of the heated walls with a starting...

Tried to figure this out for a friend but couldn't quite get it. Here is the problem. For 3 hours one winter afternoon, outside temp is 0* C. A house is heated and kept at 20* C with the expenditure of 45 kwh. What was the average energy leakes in joules per second through the walls of the...

Hello I am not a science scholar but just a gifted middle-schooler. Anyway i was wondering, is it possible to heat water past super-heated steam? If it does then what does it turn into? And please don't mock me if this is a stupid question because I see the forums and see over-complicated...

Hi, Can anyone explain exactly why in field emission you get Nottingham heating? I can understand that you get joule/ resistive heating that makes sense. I can understand that you get cooling, the electron leaves the metal there is a loss of energy. But why does it matter if it is above...

If you heat up a glass flask why will the weight of the flask decrease slightly? The lab we're doing deals with the ideal gas law, so maybe it has to do with the mass being inversely proportional to the temperature? Or is there another reason? Also, what would happen if you heat up a flask...

The experiment is joule heating and I'm trying to calculate the filament resistance.1.) mass of the calorimeter cup 49.5g specific heat of the aluminum cup: 0.22 cal/kg*K mass of calorimeter cup w/ water 232.5g initial water temp. 20.5 C voltage across heater 7.3V current through heater 5A final...

Homework Statement i've been asked to compare the efficiency of a photo voltaic cell and a solar heating cell (an array of pipes). both will be exposed to a 150W bulb for an equal amount of time. Homework Equations for photo cell: P=IV for heating panel: P=fcT f=flow rate...

I am doing some basic heat calculations about a CW laser illuminated tungsten tip (which should be used for photoemission) - I started to play with the tip geometry to try and find a way to get more flux Watts/metre^2 onto the tip without it melting. I found that after solving the 1d heat...

Homework Statement The turbine produces current that is at 12kV. To lessen the problem of Ohmic heating, a transformer steps up the voltage to 138kV for power line tranmission. Homework Equations Np/Ns=Vp/Vs ?

Homework Statement How can you heat 1 \,\mathrm{kg} mineral water which is at a temperature of 0 \,{}^\circ \mathrm{C} to at least 60 \,{}^\circ \mathrm{C} with using 1 \,\mathrm{kg} plain water at a temperature of 100 \,{}^\circ \mathrm{C}? Homework Equations \Delta Q = mc\Delta T The...

I went to walmart and found these self heating drinks/soups. All you have to do is twist a knob and wait a couple minutes and its ready. After looking online i wasn't able to get a straight answer. Is there a difference between the warming chemicals in the soups vs. hand warmers. I'm looking...

Homework Statement A solar hot-water-heating system consists of a hot water tank and a solar panel. The tank is well insulated and has a time constant of 64 hr. The solar panel generates 2000 Btu/hr during the day, and the tank has a heat capacity of 2 degrees F per thousand Btu. If the...

How can we boil water without heating it?

When heating a hydrate with a crucible and bunsen burner, why would this procedure, may not give good results for some hydrates?

Hello! The question about which oil that is the best to fry in, or to deep-fry in, should be examined, if it hasn't been already. Is it possible to set up a function b_f(T), where b is the "badness" of heating up a certain kind of fat f to temperture T? For example, saturated fat can be...

[b]1. I have a relatively simple question, but I can't think of the answer. A high bp hydrocarbon (X) is obtained by the fractional distillation of crude oil. (X) is then heated in the presence of silicate materials. only 3 new hydrocarbons were from this proces. All I want to know is what...

How many pounds of western subbituminous coal would be needed to heat the house (house requires 1,000,000 BTU), with a 60% efficient furnace? Subitiminous coal = 10,750 BTU/lb 1,000,000 BTU ____________ = 93.02 lb of coal. 10,750 Btu/lb And I am not exactly sure how...

I hope some one can help with this. 2 different but identical rated elements are used for exactly the same purpose, the only difference between the 2 is, one has the element bent into three outer coils and three inner coils, the other has four outer coils and four inner coils, the one with...

Problem 1: Homework Statement An ideal gas is heated reversibly at constant volume from T1 to T2. Calculate the entropy change of the system, the surroundings, and the universe. Homework Equations dS = dq/T (reversible change) and dq = CvdT (constant V) The Attempt at a Solution I know how...

I need to heat styrene to its forming temp of around 325 degrees F. I have a heating gun that operates at too many amps to use safely at home. So I found these temp controllers that don't use a lot of energy, but can get hotter then my blow dryer can, yet not as hot as the 700 degree heat gun I...

Basically, what we're looking to construct is a very small heating apparatus. We need to find an appropriate material to heat 28.26 cm sq., to roughly 150C or 423 K. We would prefer to use a battery mounted system but are equally ok with making some sort of plug-in system. We're not...

Q:can anyone explain heating effect E=I2Rt? and heating effect in a resistor?

why do visible light have less heating affect than infra red radiations ,in spite of the fact that photon of visible light have more energy...