Q.1
When heat is transferred by molecular collision, it is referred to as heat transfer by
Q.2
Stefan Boltzmann law is applicable for heat transfer by
Q.3
A non-dimensional number generally associated with natural convection heat transfer is
Q.4
The value of Prandtl number for air is about
Q.5
A steam pipe is to be insulated by two insulating materials put over each other. For best results
Q.6
Total heat is the heat required to
Q.7
Sensible heat is the heat required to
Q.8
The emissive power of a body depends upon its
Q.9
The amount of radiation mainly depends upon the
Q.10
When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by
Q.11
Film coefficient is defined as Inside diameter of tube
Q.12
Thermal diffusivity is a
Q.13
The most commonly used method for the design of duct size is the
Q.14
All radiations in a black body are
Q.15
The heat is transferred by conduction, convection and radiation in
Q.16
Heat is transferred by all three modes of transfer, viz. conduction, convection and radiation in
Q.17
The radiation emitted by a black body is known as
Q.18
The amount of heat flow through a body by conduction is
Q.19
Thermal conductivity of water at 20°C is of the order of
Q.20
Reynolds number (RN) is given by (where h = Film coefficient, l = Linear dimension, V = Velocity of fluid, k = Thermal conductivity, t = Temperature, ρ = Density of fluid, cp = Specific heat at constant pressure, and μ = Coefficient of absolute viscosity)
Q.21
An ordinary passenger aircraft requires a cooling system of capacity.
Q.22
A cube at high temperature is immersed in a constant temperature bath. It loses heat from its top, bottom and side surfaces with heat transfer coefficients of h₁, h₂ and h₃ respectively. The average heat transfer coefficient for the cube is
Q.23
Moisture would find its way into insulation by vapour pressure unless it is prevented by
Q.24
The ratio of surface convection resistance to the internal conduction resistance is known as
Q.25
The heat transfer by conduction through a thick sphere is given by
Q.26
The value of the wave length for maximum emissive power is given by
Q.27
The value of the wavelength for maximum emissive power is given by
Q.28
The thickness of thermal and hydrodynamic boundary layer is equal if Prandtl number is
Q.29
Thermal conductivity of air with rise in temperature
Q.30
Thermal conductivity of water in general with rise in temperature
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