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The ends of the two rods of different materials with their thermal conductivities, radii of cross – section and length in the ratio 1:2 are maintained at the same temperature difference. If the rate of flow of heat through the larger rod is 4 cal |s, what is the rate of flow through the shorter

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What are thermal radiation? Write its properties of thermal

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An indirectly heated filament is radiating maximum energy of wavelength `2.16xx 10^(-7)m`. Find the net amount of heat energy lost per second per unit area, the temperature of surrounding air is `13^oC`. Given `b = 2.88xx10^(-3) mk, σ = 5.77xx10(-8)

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Animals in the forest find shelter from cold in holes in the snow.

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A brass boiler has a base area of `0.15m^2` and thickness 1.0cm. It boils water at the rate of 6kg| min when placed on a gas stove, Estimate the temperature of the part of flame in contact with the boiler. Thermal conductivity of brass `= 10^9J|s|m|'^oC`, heat of vaporization of water `=

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How do you explain heating of rooms based on principle of

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Why is the energy of thermal radiation less than that of visible

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Two rods A and B are of equal length. Each rod has its ends at temperature T1 and T2 (T1 > T2). What is the condition that will ensure equal rates of flow through the rods A and

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A Sphere is at a temperature of 6oo k. Its cooling rate is R in an external environment of 200k. If temperature falls to 400k. What is the cooling rate R1 in terms of

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If the temperature of the sun is doubled, the rate of energy received on each will increases by what

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How do you explain the emission of long - wavelength by the object at low

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If the radiation from the moon gives maxima at `λ = 4700 A^o and λ = 14xx10^(-6)m`. What conclusion can be drawn from the above

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Differentiate between conduction, convection and

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The tile floor feels colder than the wooden floor even though both floor materials are at same temperature.

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A spherical black body of radius 12cm radiates 450w power at 500k. If the radius were halved and the temperature doubled, what would be the power

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A cylinder of radius R made of a material of thermal conductivity K1 is surrounded by a cylindrical shell of inner radius R and other radius 2R made of material of thermal conductivity K2. The 2 ends of combined system are maintained at two different temperatures. There is no loss of heat across the clinical surface and the system is in steady state calculate the effective thermal conductivity of the

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A room has a 4m x 4m x10cm concrete roof `(K_1 = 1.26w|m|'^oC)`. At some instant, the temperature outside is `46^oc` and radius `32^oc`. 1) Calculate amount of heat flowing per second into the room through the roof. 2) If bricks `(K_2 – 0.56w |m|'^oc)` of thickness 7.5cm are laid down on roof, calculate the new rate of heat flow under the same temperature

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A bar of copper of length 75cm and a bar of length 125cm are joined end to end. Both are of circular cross – section with diameters 2cm. The free ends of copper and steel are maintained at `100^oc and 0^oc` respectively. The surfaces of the bars are thermally insulated. What is the temperature of copper – steel junction? Thermal conductivity of copper `= 9.2xx10^(-2)k cal |m|'^oc|s` and that of steel is `1.1xx10^(-2) k

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If air is a bad conductor of heat, why do we not feel warm without

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A body with large reflectivity is a poor emitter

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