Colburn analogy is applicable for the value of Prandtl number from_________________?

A. 0.001 to 1
B. 0.6 to 120
C. 0.5 to 5
D. 120 to 400

For a given ambient air temperature with increase in the thickness of insulation of a hot cylindrical pipe, the rate of heat loss from the surface would ?

A. Decrease
B. Increase
C. First decrease and then increase
D. First increase and then decrease

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________________?

A. 40.5
B. 34.4
C. 26.8
D. 25

In a heat exchanger, floating head is provided to____________________?

A. Facilitate cleaning of the exchanger
B. Increase the heat transfer area
C. Relieve stresses caused by thermal expansion
D. Increase log mean temperature gradient

Grashoff number, which is defined as g . β (Ts – T∞) ρ2. L3/μ2, is proportional to the ratio of buoyancy force to ____________ force?

A. Viscous
B. Elastic
C. Inertial
D. None of these

LMTD can’t be used as such without a correction factor for the_________________?

A. Multipass heat exchanger
B. Baffled heat exchanger
C. Condensation of mixed vapour in a condenser
D. All A. B. and C.

Prandtl number is given by__________________?

A. CP μ/a
B. hD/k
C. CP μ/k
D. μ/h CP

The Fourier number (defined as a.t/L2) is used in the analysis of problem involving heat transfer by_______________?

A. Forced convection
B. Natural convection
C. Transient conduction
D. Steady state conduction

Heat transfer by radiation between two bodies at T1 & T2 and in an ambient temperature of Ta°C depends on_____________?

A. T1 – T2
B. T1 – Ta
C. T2 – Ta
D. None of these

Which of the following has the minimum absorptivity ?

A. Aluminium foil
B. Coal dust
C. Refractory bricks
D. Iron plates