Q. “All the factors relating to geometry of the sections are grouped together into a multiple constant called the shape factor” True or false

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Q. Shape factor for plane wall is equal to

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Q. For a prescribed temperature difference, bodies with the same shape factor will allow heat conduction proportional to

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Q. Shape factor for cylinder is

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Q. The annealing furnace for continuous bar stock is open at the ends and has interior dimensions of 0.6 m * 0.6 m * 1.5 m long with a wall 0.3 m thick all around. Calculate the shape factor for the furnace?

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Q. Shape factor for sphere is

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Q. Which is true regarding a complete rectangular furnace?

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Q. The shape factor for complete rectangular furnace is
Where a, b and c are the inside dimensions and d x is the wall thickness

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Q. For the same material and same temperature difference, the heat flow in terms of shape factor is given by

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Q. For the same amount of fabrication material and same inside capacity, the heat loss is lowest in

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Q. With variable thermal conductivity, Fourier law of heat conduction through a plane wall can be expressed as

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Q. The inner and outer surfaces of a furnace wall, 25 cm thick, are at 300 degree Celsius and 30 degree Celsius. Here thermal conductivity is given by the relation
K = (1.45 + 0.5 * 10¯⁵ t²) KJ/m hr deg

Where, t is the temperature in degree centigrade. Calculate the heat loss per square meter of the wall surface area?

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Q. A plane wall of thickness δ has its surfaces maintained at temperatures T₁ and T₂. The wall is made of a material whose thermal conductivity varies with temperature according to the relation k = k₀ T². Find the expression to work out the steady state heat conduction through the wall?

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Q. The mean thermal conductivity evaluated at the arithmetic mean temperature is represented by

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Q. With respect to the equation k = k0 (1 +β t) which is true if we put β = 0?

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Q. If β is greater than zero, then choose the correct statement with respect to given relation
k = k0 (1 +β t)

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Q. The unit of thermal conductivity doesn’t contain which parameter?

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Q. The temperatures on the two sides of a plane wall are t1 and t2 and thermal conductivity of the wall material is prescribed by the relation
K = k0 e^(-x/δ)

Where, k0 is constant and δ is the wall thickness. Find the relation for temperature distribution in the wall?

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Q. “If β is less than zero, then with respect to the relation k = k0 (1 + β t), conductivity depends on surface area”. True or false

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Q. A cable of 10 mm outside is to be laid in an atmosphere of 25 degree Celsius (h = 12.5 W/m² degree) and its surface temperature is likely to be 75 degree Celsius due to heat generated within it. How would the heat flow from the cable be affected if it is insulated with rubber having thermal conductivity k = 0.15 W/m degree?

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