Test: Heat Transfer - 1 - Mechanical Engineering MCQ

Which of the following is generally considered as opaque surface towards radiations?

Black liquor generated during paper manufacture is concentrated in a

When vaporisation takes place directly at the heating surface, it is called

Steam consumption in kg/hr in case of an evaporator is given by (where, C & E are capacity the economy of the evaporator respectively)

Reynold's analogy states that

With increase in temperature, the thermal conductivity of non-metallic amorphous solids

Fourier's law applies to the heat transfer by

Shell side pressure drop in a shell and tube heat exchanger does not depend upon the

In the equation Q = UAΔt; Δt is

With increase in porosity, the thermal conductivity of a solid substance

For an ideal black body

In Joule's experiment, an insulated container contains 20 kg of water initially at 25�C. It is stirred by an agitator, which is made to turn by a slowly falling body weighing 40 kg through a height of 4 m. The process is repeated 500 times. The acceleration due to gravity is 9.8 ms^-2. Neglecting the heat capacity of agitator, the temperature of water (in �C) is

Fouling factor

In case of vertical tube evaporator, with increase in liquor level, the overall heat transfer co-efficient

The steam ejector is used to

For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area

The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)_R and the co-efficient of performance as a heat pump (COP)_HP are

Hot water (0.01 m³ /min) enters the tube side of a counter current shell and tube heat exchanger at 80�C and leaves at 50�C. Cold oil (0.05 m³/min) of density 800 kg/m³ and specific heat of 2 kJ/kg.K enters at 20�C. The log mean temperature difference in �C is approximately

In a heat exchanger, floating head is provided to

Leidenfrost point is a term concerned with the

A process stream of dilute aqueous solution flowing at the rate of10 Kg.s^-1 is to be heated. Steam condensate at 95�C is available for heating purpose, also at a rate of 10 Kg.s^-1. A 1 - 1 shell and tube heat exchanger is available. The best arrangement is

Heat produced when a steady state current, I passes through an electrical conductor having resistance, 'R' is