Q.1.
From the concept of kinetic theory, mean travel velocity of the gas molecules is prescribed by the relation
- a) V = (3M/GT) 1/2
- b) V = (3GT/M) 1/2
- c) V = (6T/GM) 1/2
- d) V = (3GT/2M) 1/2
Q.2.
Low temperature insulation are used when the enclosure is at a temperature lower than the ambient temperature. Which one of the following is not a low temperature insulation?
- a) Asbestos
- b) Cork
- c) Cattle hair
- d) Slag wool
Q.3.
The value of Lorenz number in 10-8 W ohms/K2 is
- a) 2.02
- b) 2.35
- c) 2.56
- d) 2.45
Q.4.
For liquids, thermal conductivity is governed by the relation
- a) k = A c p p7/3/M1/3
- b) k = 2A c p p4/3/M2/3
- c) k = A c p p4/3/M1/3
- d) k = A c p p8/3/M1/3
Q.5.
Consider the following parameters
- a) i and ii
- b) i, ii, iii and iv
- c) i and iii
- d) i, ii and iii
Q.6.
The thermal conductivity and the electrical conductivity of a metal at absolute temperature are related as
- a) k/σ T
- b) k/σ
- c) k σ/T
- d) k/T
Q.7.
The relation Ϫ2 t =0 is referred to as
- a) Poisson’s equation
- b) Fourier heat conduction equation
- c) Solution for transient conduction
- d) Laplace equation
Q.8.
The unit of thermal diffusivity is
- a) m2/hr-K
- b) kcal/m2-hr
- c) m2/hr
- d) m/hr-K
Q.9.
To effect a bond between two metal plates, 2.5 cm andcm thick, heat is uniformly applied through the thinner plate by a radiant heat source. The bonding must be held atK for a short time. When the heat source is adjusted to have a steady value of 43.5 k W/ma thermocouple installed on the side of the thinner plate next to source indicates a temperature ofK. Calculate the temperature gradient for heat conduction through thinner plate. In the diagram, the upper plate is 2.5 cm thick while the lower iscm thick.
- a) – 1000 degree Celsius/m
- b) – 2000 degree Celsius/m
- c) – 3000 degree Celsius/m
- d) – 4000 degree Celsius/m
Q.10.
The diffusion equations
- a) Temperature doesn’t depends on time
- b) There is no internal heat generation
- c) Steady state conditions prevail
- d) There is no internal heat generation but unsteady state condition prevails