All radiations in a black body are
Reflected
Refracted
Transmitted
Absorbed
- The heat is transferred by conduction, convection and radiation in
- The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer…
- According to Wien's law, the wavelength corresponding to maximum energy is proportion to
- The unit of overall coefficient of heat transfer is
- Radiation is the process of heat transfer in which heat flows from a ________, in a straight line, without…
- In case of liquids and gases, the heat transfer takes place according to
- Which of the following has least value of conductivity?
- When absorptivity (α) = 1, reflectivity (ρ) = 0 and transmissivity (τ) = 0, then the…
- The process of heat transfer from one particle of the body to another is called conduction, when the…
- Two plates spaced 150 mm apart are maintained at 1000°C and 70°C. The heat transfer will take…
- The energy distribution of an ideal reflector at higher temperatures is largely in the range of
- The value of the wavelength for maximum emissive power is given by
- In free convection heat transfer transition from laminar to turbulent flow is governed by the critical…
- Which of the following property of air does not increase with rise in temperature?
- The amount of heat flow through a body by conduction is
- The heat transfer takes place according to
- Two balls of same material and finish have their diameters in the ratio of 2: 1 and both are heated…
- Sensible heat factor is given by (where S.H. = Sensible heat, and L.H. = Latent heat)
- According of Kirchhoff's law
- The critical thickness of insulation for a sphere is
- An ordinary passenger aircraft requires a cooling system of capacity.
- The product of Reynolds number and Prandtl number is known as
- According to Newton's law of cooling, the heat transfer from a hot body to a cold body is
- The value of the wave length for maximum emissive power is given by
- An electric cable of aluminium conductor (k = 240 W/mK) is to be insulated with rubber (k = 0.15 W/mK).…
- A grey body is one whose absorptivity
- Reynolds number is the ratio of
- Heat is transferred by all three modes of transfer, viz. conduction, convection and radiation in
- Metals are good conductors of heat because
- Two long parallel surfaces each of emissivity 0.7 are maintained at different temperatures and accordingly…