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It's really unanswerable. Defects in a metal do decrease its thermal conductivity, but heat can either cause stress and create dislocations (because application of heat causes temperature differences inside the material) or can cause annealing (the crystal structure can 'relax' to near-perfect, and erase the dislocations). In electrical solder, heat can ...


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The formula is valid, but you have to consider $Q$ to be the net amount of heat transferred into the water. In both cases, as the water gets hot, it will radiate some heat to the environment (because the region above the water is cooler). In addition, the lidless pot will lose heat (and some mass) through evaporation. The problem is that the amount of ...


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Here you are considering 2 different processes: in case 1 the process occurs at constant pressure (that of the atmosphere); in case 2 it occurs at constant volume (that of the pot). The coefficients that relate the heat exchanged in the process with the change in temperature are the (molar) heat capacity at constant pressure $c_p$ and constant volume $c_v$ ...


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Here, in the case of your question, the brass rod and the steel rod are connected in parallel combination in between the hot reservoir and the cold reservoir. So, the thermal resistance will be given by, 1/Rp = (k1A1+k2A2)/l..... And, we know that, Q/t = dT/Rp = (k1A1+k2A2)*dT/l. You have been given the values of Q, t, k1, k2, A1, and dT. So, you can easily ...


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This equation describes 3D transient heat conduction in a material, where $\alpha$ is the thermal diffusivity. The thermal diffusivity is related to the thermal conductivity, the heat capacity, and the density by $\alpha=\frac{k}{\rho C}$. The equation is derived by performing a differential heat balance on an infinitesimal volume of the material. It can ...


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The separation of water molecules in ice is greater than in water (liquid); they have a more open structure. So ice is less dense than water. However when ice melts groups of molecules retain an ice like structure. As the temperature rises these group of molecules break up and occupy a smaller volume hence increasing the density of water (liquid). At ...


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First let us consider your quote" for the same volume structure concrete houses will require much more energy for same temperature rise ". It, thus, tell that concrete will absorb much more heat from room to rise its temperature whereas wood will absorb less heat to rise to same temperature and keep room warm. Then I thought concrete is better conductor ...


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Axial conduction, along the cylinder Let's first talk about electricity. We know that effective resistance of a parallel portion of a circuit found by the relation: $$\frac{1}{R} = \sum \frac{1}{R_i}$$If you just figure out the relation between conductance and resistance, $$G = \frac{1}{R}$$So $G = \sum G_i $. In fact, conductance in parallel is additive, ...


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Putting a dark material onto snow does increase the melting rate, and indeed soot from pollution is having exactly this effect. The mechanism is exactly as you suggest. Soot absorbs sunlight and heats up, and the heat is transferred to the snow by conduction and convection. Using clean oil wouldn't work very well because oil does not absorb sunlight ...


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You don't have convection in a solid, you need a liquid or gas where hotter, less dense portions can rise above the colder, denser ones. With thick walls, the answer is the same What do you consider a "significant" temperature gradient? The gradient is the driving force behind heat conduction, so you certainly can't ignore it. Modeling thick walls: you ...



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