Q. The value of convective coefficient of air in case of free convection is

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Q. The fluid particles move in flat or curved un-mixing layers or streams and follow a smooth continuous path. This type of flow is known as

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Q. The characteristic dimension d in the relation R E = V d p/δ is the equivalent diameter and is defined as how many times the cross-sectional flow area divided by wetted perimeter

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Q. For a duct of rectangular cross-section with length l and breadth b, the value of d e is

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Q. In many flow situations, the duct can be

(i) Circular
(ii) Rectangle
(iii) Trapezoidal
(iv) Annulus

Identify the correct option

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Q. If an annulus has an inner diameter of d₁ and an outer diameter of d₂ then the equivalent diameter is

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Q. Conduction plus fluid flow in motion is known as

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Q. How many types of convection are there?

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Q. Which of the following heat flow situations pertains to free or natural convection?

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Q. Mark the system where heat transfer is given by forced convection

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Q. Forced convection in a liquid bath is caused by

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Q. A finned tube hot water radiator with a fan blowing air over it is kept in rooms during winter. The major portion of the heat transfer from the radiation is due to

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Q. A body cooling from 80 degree Celsius to 70 degree Celsius takes 10 minutes when left exposed to environmental conditions. If the body is to cool further from 70 degree Celsius to 60 degree Celsius under the same external conditions, it will take

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Q. On a summer day, a scooter rider feels more comfortable while on the move than while at a stop light because

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Q. What is the value of convective coefficient of oil in case of forced convection?

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Q. A sphere, a cube and a thin circular plate, all made of the same material and having the same mass are initially heated to the temperature of 250 degree Celsius. When left in air at room temperature, what will be their response to cooling?

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Q. Newton-Rikhman law is given by

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Q. The value of film coefficient is dependent upon

(i) Boundary layer configuration
(ii) Geometry and orientation of the surface
(iii) Surface conditions

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Q. The convection coefficients for boiling and condensation lie in the range

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Q. Forced air flows over a convection heat exchanger in a room heater, resulting in a convective heat transfer coefficient 1.136 k W/m² K. The surface temperature of heat exchanger may be considered constant at 65 degree Celsius, and the air is at 20 degree Celsius. Determine the heat exchanger surface area required for 8.8 k W of heating

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