Heat Transfer Which of the following has the lowest Prandtl number? Water Dilute H₂SO₄ Molten sodium (a coolant used in fast breeder reactor) Transformer oil Water Dilute H₂SO₄ Molten sodium (a coolant used in fast breeder reactor) Transformer oil ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer In a heat exchanger with steam outside the tubes, a liquid gets heated to 45°C, when its flow velocity in the tubes is 2 m/s. If the flow velocity is reduced to 1 m/s, other things remaining the same, the temperature of the exit liquid will be Less than 45°C Equal to 45°C Initially decreases and remains constant thereafter More than 45°C Less than 45°C Equal to 45°C Initially decreases and remains constant thereafter More than 45°C ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer A composite wall consists of two plates A and B placed in series normal to the flow of heat. The thermal conductivities are kA and kB and the specific heat capacities are CPA and CPB for plates A and B respectively. Plate B has twice the thickness of plate A. At steady state, the temperature difference across plate A is greater than that across plate B, when CPA < CPB CPA > CPB KA>2 kB KA < 0.5kB CPA < CPB CPA > CPB KA>2 kB KA < 0.5kB ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer The rate of heat transfer is a product of overall heat transfer co-efficient, the difference in temperature and the Nusselt number Heat transfer area Heating volume None of these Nusselt number Heat transfer area Heating volume None of these ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the Temperature gradient produced due to density difference None of these Buoyancy of the bubbles produced at active nucleation site Existence of thermal boundary layer Temperature gradient produced due to density difference None of these Buoyancy of the bubbles produced at active nucleation site Existence of thermal boundary layer ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer A steel sphere of radius 0.1 m at 400°K is immersed in an oil at 300°K. If the centre of the sphere reaches 350°K in 20 minutes, how long will it take for a 0.05 m radius steel sphere to reach the same temperature (at the centre) under identical conditions ? Assume that the conductive heat transfer co-efficient is infinitely large. 40 minutes 10 minutes 5 minutes 20 minutes 40 minutes 10 minutes 5 minutes 20 minutes ANSWER DOWNLOAD EXAMIANS APP
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