Transport Phenomena Mid - I, September - 2014

1.Heat transfer by conduction is described by
  • Fourier’s law
  • Newtons Law
  • Stefan-boltzmann law
  • Fick’s law
Answer: A
2.The units of thermal conductivity in SI units
  • W/(m.k)
  • J/(m.k)
  • W/(m2.k)
  • J/(m2.k)
Answer: A
3.The thermal conductivity of a gas is
  • Decreases with increasing temperature
  • Increases with increasing temperature
  • Independent of temperature and pressure
  • None
Answer: A
4.Thermal conductivity is minimum for
  • Asphalt
  • water
  • petroleum coke
  • air
Answer: D
5.The binary diffusivity in gases at atmospheric conditions is of the order of
  • 10-1 cm2/sec
  • 10-5 cm2/sec
  • 105 cm2/sec
  • 10-7 cm2/sec
Answer: A
6.The Schimdt number is defined as
  • μ/DAB
  • μ/ρDAB
  • ρμ/DAB
  • μ DAB/ρ
Answer: B
7.according to the film theory the mass transfer coefficient is directly proportional
  • DAB
  • DAB 0.5
  • DAB 2
  • DAB 1.5
Answer: A
8.The velocity of a fluid in a pipe flow is maximum
  • At the wall
  • in the centre
  • in between centre and wall
  • None
Answer: B
9.The boundary layer exists on account of
  • Fluid viscosity
  • fluid density
  • gravitational effect
  • surface tension
Answer: A
10.Thermal conductivity is maximum for
  • Coke
  • gasoline
  • steel
  • air
Answer: C
11.Diffusivity has the same dimensions as _______________________Viscosity.
Answer: Kinematic
12.Thermal diffusivity has the dimensions of_________________
Answer: m2/sec
13.At liquid gas interfaces momemtum flux in the liquid phase is very nearly__________________
Answer: Zero
14.The basic requirement for the rate of heat transfer by convection under steady state condition is ______________________
Answer: h A Δ T
15.Thermal conductivity of gases at low density increases with _______________temperature.
Answer: Increasing
16.Euken formula or the prandtl number of a non polar polyatomic gas at low density is_____________
Answer: Pr = Cp/Cp + 1.25R)
17.Force acting on a particle moving through a fluid are gravity force, ______________and drag force.
Answer: Buoyancy force
18.Lewis number is the ratio of__________________
Answer: Thermal diffusivity/mass diffusivity
19.According to the penetration theory the mass transfer co-efficient is directly proportional to ________________
Answer: DAB 0.5
20.The Sherwood number is defined as ______________________
Answer: Kcd/DAB