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Two metal boxes A and B with heat capacity C and 2 C respectively are interconnected by a rod of length l, cross-sectional area A and Thermal conductivity k. At t=0, temperature of A and B is 40°C and 70°C respectively. Find time t when temperature of A is 50°C.

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Important Questions on Thermal Properties of Matter

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In an experiment with a continuous flow calorimeter, an input power of 50 W produced a rise of 50°C in the liquid. When the power was tripled, the same temperature rise was achieved by making the rate, of flow of liquid $n$ times its initial value. If the power lost to the surrounding in each case is 25 W, value of n is
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A brass rod and an aluminium rod each of length 1 m and same cross section area 1 cm2 are placed in contact with each other as shown. Temperature of both the rods is raised by 100 K. The coeffcients of linear expansion of brass and aluminium are 2.0×10-5 K-1 and 2.4×10-5 K-1 respectively. If the Young's moduli of brass and aluminium are 1011 N m2 and 7×1010 N m2 respectively then stress in the rods is

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Two metallic rods of equal length and cross-section but thermal conductivities K1 and K2 are welded together end to end. The resulting thermal conductivity of this resulting rod will be
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A metal sphere having inner radius a and outer radius b has thermal conductivity K=K0r2(arb). The thermal resistance between inner and outer surface for radial heat flow is
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The figure shows the face and interface temperature of a composite slab consisting of four materials, of identical thickness, through which the heat transfer is steady. Which material has maximum thermal conductivity?

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In a room where the temperature is 30 °C, a body cools from 61 °C to 59 °C in 4 min. The time (in min) taken by the body to cool from 51 °C to 49 °C will be
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A block of ice at -10°C is slowly heated and converted to steam at 100°C. Which of the following curves represent the phenomenon qualitatively?
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The wavelength corresponding to maximum spectral radiancy of a black body A is λA=5000 Ao. Consider another black body B whose surface area is twice that of A and total radiant energy emitted by B is 16 times that emitted by A. The wavelength corresponding to maximum spectral radiancy for B will be