What is Heating: Definition and 616 Discussions

A laser beam whose intensity is modulated (at frequency, f) is falling on a black absorber. For the surface temperature, there will be two components: (1) modulated temperature or photothermal wave and (2) a static dc temperature component. The photothermal signal properties are well known...

I ran an experiment in which a Daniell Cell (using Cu and Mg electrodes with Cu Nitrate and Mg Nitrate as the electrolytes (both 0.1mol)) was heated on both sides by using two beakers filled with water, the water that heated the cell was heated to about 92C and then left to cool. The experiment...

After typing all of that out, I think I got it, thanks! Homework Statement I am working on a project to build a biodiesel reactor. The heating system of said reactor is provided by a loop of pipe containing a pump (1 HP, 36 litres per minute (9.5 gal), 50m max head (164 ft)), a hot water...

If a probe entering the Earth's atmosphere heats up because it encounters the atmosphere, then why don't jet airplanes (for example) also get really hot? They are flying around in the same atmosphere that heats up the probe when it re-enters the Earth's atmosphere.

Homework Statement A solar panel (an assemblage of solar cells) measures 58 cm x 53 cm. When facing the sun, this panel generates 2.7A at 14V. Sunlight delivers an energy of 1.0 x 10^3 W/m^2 to an area facing it. What is the efficiency of this panel, that is, what fraction of the energy in...

Homework Statement Two heating coils have resistances 12.0 ohms and 6.0 ohms, respectively. a)What is the Joule heat generated in each if they are connected in parallel to a source of emf of 115V? b) What if they are connected in series.Homework Equations Am I doing this question properly? The...

Homework Statement The aluminum cable of a high-voltage transmission line carries a current 600A. The cable is 60km long, and it has a diameter of 2.5 cm. What is the power lost to Joule heating in this cable? Homework Equations Should I use the equation V=1/(4piEo)integral(dq/r) to...

Hi there, I've been interested in this induction heating thing and would like to build one. Its quite a long time searching the net and experimenting to make it work. I've been stuck with the pll issue. My configuration is Hbridge which is fed from a simple power supply(not split) so the lowest...

Why do substances expand on heating? Please give an understandable molecular account of the process of expansion.

Homework Statement Coffee maker, whose output of 650 W, producing coffee. Kettle to the boil 5.0 dl of water, with an initial temperature of 14 ° C. Heat capacity of water is 4.19 kJ / (kg ° C) and water density of 1.0 kg/dm3 Homework Equations How long does it take a coffee water...

I need a solution for healing tree grafts. Fruit trees are often propagated in the spring by grafting (attaching) a piece of scion wood to rootstock. The graft must "heal" which means that the outer "cambium" layers of the two pieces join together. This process occurs around room temperature...

Hello, I have this problem that I am struggling with. I have a heating element that is submerged in a water tank. The temperature of the water in the tank starts at say 5C. The temperature of the water flowing through the heating element is at 90C. I can also assume that the metal of the...

Homework Statement Say we have a warehouse with a 5 hr time constant. The outside temp is 16C at 2:00AM, and 32C at 2:00PM. The warehouse is at 24C at noon. What will the temp be at 6:00 pm? When will the temp be 27C? The Attempt at a Solution First, I set up a sine wave for the...

Does anybody know how this works? https://www.youtube.com/watch?v=aLwaPP9cxT4

hi all :) im trying to heat a metal wire in my experiment and because i don't have a heat sensor camera or an oven,... i thought of using a sand bath to control the heating temperature. is it possible to heat a wire upto 500~600 degree celcius by sand bath? (or whatever bath that may be...

Homework Statement Metals do have negligible penetration depth at higher frequencies considering microwave and infrared range.so microwaves are reflected by metals.but it is observed that metal powders when compacted under pressure to a certain porosity level nearly 10 to 30% porosity,have...

Given: a two-story residence currently with separate basement and attic gas forced air furnaces-chillers. The basement furnace is a recently updated high efficiency (96%) hybrid heat pump/aux gas heat at around 80,000 btuh (out); the attic unit is much less efficient and maybe 60-70,000 btuh...

Hi everyone. I want to heat a piece of Rubber by embedding copper strips or wires in it and passing electricity(120V - 2.5Amp) through it. The room temperature is 0(zero) deg Celsius and i want to heat the aluminum block(5" x 5" x 1") to 10 deg Celsius(Not more than 10 deg). Question...

Homework Statement A thin infinitely long plate is heated in the middle of one of the short edges. What is the temperature profile T(x,y)? Homework Equations \bigtriangledown^2T = 0 The Attempt at a Solution I know how to find T(x, y) that's not the problem the question is more why is...

A rigid tank has a volume of 0.01m3. It initially contains saturated water at a temperature of 200°C and a quality of 0.4. The top of the tank contains a pressure-regulating valve that maintains the vapor at constant pressure. This system undergoes a process whereby it is heated until all the...

Hi, As part of my final year project I have to heat air within an exclosed environment (i.e. a 1m x 1m x 1m insulated box) to test the effectiveness of using phase change materials to regulate ambient air temperature. To do this I need to slowly heat the air inside the box at a rate that...

Homework Statement What happens when gas is heated? Is all of the absorbed energy converted to kinetic energy? or is some of the absorbed energy converted into potential and some into kinetic energy? Homework Equations The Attempt at a Solution My teacher said the correct answer...

Curious question, figured what better place to ask than the physics forum. So I just picked up a used hot tub. Was running great when I bought it. Filled it up with water, turned it on, started its cycle. It can take over 24 hours for the tub to reach 102 degrees. There's a 12 inch...

Nonlinear Dielectric Heating and more! Hello all, Here is an interesting query for some work I am trying to figure out. Everyone knows about dielectric heating, which is the principle on which microwave ovens operate. Without deriving the formula for the power dissipated into an object...

Specific Heat Capacity Lab I conducted a lab where I heated 100ml of water using a heating coil with a current of 4A passing through it. The temperature data turned out beautifully, with the temperature rising evenly until it plateaued just under 100 degrees celsius as it began to change phase...

If we can heat a gas so that the electrons "fly" off, can we heat one so that the protons do?

Hi. Im trying to measure the efficiency of a heat engine. I therefore need to work out what the input energy is to the heat engine. I have two problems. Firstly, how should I measure the heat going into the stirling rather than the heat coming out of the heater. Is it ok to measure the...

I used a propane gas tank to add thermal storage to my out door wood burner. The ethyl mercaptan residue mixed in the water and the smell about drove us out of the house. I added bleach to the tank which did a fair job of killing the smell, now I need to know how to neutralize...

Homework Statement How do I calculate how hot a metal object will get if it's just left to be heated up by the sun? Homework Equations The two equations that i know of would be the specific heat capacity of the metal: Q = mCpΔT And the radiation equation: Q=εσAT^4 The Attempt at a...

how can i obtain a thermophotovoltaic device to convert solar heat from a parabolic reflector to electricity? or is there any other better device that can convert heat directly to electricity?

I need to construct a heating element powered by 9V that needs to reach 400 C. How do I figure out what length of wire I will need. I will most likely be using nichrome or kanthal A1

looking to find out what it take to retro-fit a small elementry school ( 3,000sqft) with new base board heater or small boiler. to calculate the different fuels (electric vs natural gas) and amounts used? In NW: older rates (just for calculations) electric is $.0463/kWh vs 1st 2,000...

Hi guys, For today's lunchtime challenge... If I put 1kw of electrical energy into a heating element and get X amount of heat out, why can't I put ~X amount of heat into the element and get ~1kw of electricity out? ( I accept less than 100% reverse process ability) what's the mechanism...

Homework Statement I'm struggling to explain why for an ideal gas at constant pressure heating by burning fuel is equivalent to reversible heating. I know that all forms of work on a ideal gas are eqivalent but don't know why. Homework Equations The Attempt at a Solution

Homework Statement Initially, 2 kg of water is at 250 Celsius and it exists as a saturated liquid. It is now isobarically heated until all of it is converted to saturated vapor. Find final temperature and volume. Homework Equations Thermodynamic tables and the use of interpolation...

I know there are some obstacles to overcome, but I'm wondering how good the idea would be in theory. First though, a few sub-questions before the main one: 1: The radiation in a microwave food cooker is like a laser (hence the 'hotspots' in food). Is it possible for microwaves to more...

Hi all, I have made a simulation of resistive heating in Comsol which is basically a gold wire surrounded by air is exposed to 0.1 V and I got the temperature distribution. The numbers seem really high (The temperature is at 2000 K where the ambient temperature is 293) and I would like to make...

Homework Statement Hi! I apologize in advance for my knowledge of vocabulary in this topic:) OK, so we have a Melde-tube 55 cm long, T=293K, with the top of it open, and a 20cm Hg part cutting off 30cm of air when is equilibrium. The original problem asked how much we can heat the air so...

lil question for anyone who may have any suggestions, I am livin in a house at the moment with my partner and 13 month old daughter, the house is single glazed and is poorly insulated, now winters just around the corner and if last year is anything to go by, then were in for a cold one again...

Hi , I have a question that's confusing and difficult to comprehend " A heating element is placed on the floor and bag of water is placed over it. At present, A power of 300W is applied to the heating element. Peter, the technician, wants to increase the rate at which the water in the...

Dear all, I have a piece of brass material at high temperature (around 300 Celsius) and I would like to know how can I measure the heating power stored by this piece. the piece is designed in a way that we can flow a fluid through it. For low temperatures ( below 100 Celsius) it is maybe...

This is an interesting subject. There have been discovered very large (up to around 100 kpc) hot (10^7 K) intergalactic gas clouds within galaxy clusters. A simple calculation based on the density of the gas clouds in question and the emission rate of the hot gas shows the gas clouds should...

Hi If you were making MgO by heating Mg in a crucible with a lid on, why might the MgO escape when you lift the lid. Isn't MgO a solid? thanks

I want to build something like http://www.radioshack.com/product/index.jsp?productId=2911246", but much smaller and only heating a coil up to 185 C. It would need to last at least an hour, but be as compact as possible. Any suggestions?

Homework Statement A heating coil is to be made, from nichrome wire, which will operate on a 12 V supply and will have a power of 36 W when immersed in water at 373 K. The wire available has a cross-sectional area of 0.10 mm². What length of wire will be required? (Resistivity of nichrome at...

Hello, I want to do a test heating a hot dog in a tube using a Magnetron from a 900W Microwave oven. Before doing the test I would like to know if there is any reasons not to mount the magnetron antenna on top of the metal tube, or on the side. (Please see attached picture) Also, will I...

I keep thinking of doing something with Solar Power. (Southern UK) The easiest, conceptually would be very basic homemade thermal panels but then there's the problem of how to use the hot (warm) water. That involves plumbing and a special hot tank. Once you've gone for that, you may as well...

Hi guys, I am of a Mechanical Engineering background, however my dissertation has a largely optics based focus, and I am struggling with understanding the heating effect of a Laser. I will be using various wavelength ND:Yag lasers, and will be focussing them onto a target material, which...

I have a small steel cylinder centered inside a larger steel cylinder. The remaining space is filled with 60% silica sand and 40% air. I am heating the larger cylinder in a furnace at a known heating rate and I want to calculate the theoretical rate of heating of the internal cylinder. This is...

Is there an equation for the rate of heating on a surface at any time, and at any angle?