Heat Transfer — Flashcards

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The three methods of heat transfer are: conduction, convection, and radiation. Conduction happens through particle contact without particles leaving their positions. Convection happens when fluid part…

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Heat travels through the metal by conduction. In metals, free electrons carry thermal energy rapidly from the hot end to the cold end. This is why metals are good conductors of heat.

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In a fluid, the warmer, less dense part rises and the cooler, denser part moves down to replace it. This circulation transfers heat through the fluid. That is convection.

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Heat from the Sun reaches Earth by radiation. Radiation does not require any material medium and travels as electromagnetic waves with the speed of light.

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An isothermal surface is a surface at every point of which the temperature is the same. Heat flow is perpendicular to it, and two isothermal surfaces never intersect.

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Given: temperature difference = 80 °C - 20 °C = 60 °C, distance = 0.20 m. Formula: temperature gradient = (θ1 - θ2) / l Calculation: gradient = 60 °C / 0.20 m = 300 °C m^-1 Answer: 300 °C m^-1 The uni…

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Given: A = 2 m², l = 0.50 m, K = 4 W m^-1 K^-1, temperature difference = 10 K. Formula: dQ/dt = K A (θ1 - θ2) / l Calculation: dQ/dt = 4 × 2 × 10 / 0.50 W Step 1: 4 × 2 = 8 Step 2: 8 × 10 = 80 Step 3:…

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Formula: Q = K A (θ1 - θ2) t / l Here, Q is heat conducted, K is thermal conductivity, A is area, θ1 and θ2 are face temperatures, t is time, and l is the length of the slab.