GATE Prev Year : Heat-Transfer Test-3

Question 1

For the circular tube of equal length and diameter shown below, the view factor F13 is 0.17. The view factor F12 in this case will be

  • A0.17
  • B0.21
  • C0.79
  • D0.83

Question 2

One dimensional unsteady state heat transfer equation for a sphere with heat generation at the rate of ‘q’ can be written as

  • ADescription: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME 18-Mar\GATE-ME-2004_files\image061.png
  • BDescription: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME 18-Mar\GATE-ME-2004_files\image062.png
  • CDescription: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME 18-Mar\GATE-ME-2004_files\image063.png
  • DDescription: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME 18-Mar\GATE-ME-2004_files\image064.png

Question 3

Consider a laminar boundary layer over a heated flat plate. The free stream velocity isDescription: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME-28-Mar\GATE-ME-2003_files\image243.pngAt some distance x from the leading edge the velocity boundary layer thickness isDescription: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME-28-Mar\GATE-ME-2003_files\image244.pngand the thermal boundary layer thickness isDescription: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME-28-Mar\GATE-ME-2003_files\image245.pngIf the Prandtl number is greater than 1, then

  • ADescription: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME-28-Mar\GATE-ME-2003_files\image246.png
  • BDescription: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME-28-Mar\GATE-ME-2003_files\image247.png
  • CDescription: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME-28-Mar\GATE-ME-2003_files\image248.png~Description: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME-28-Mar\GATE-ME-2003_files\image249.png
  • DDescription: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME-28-Mar\GATE-ME-2003_files\image248.png~ x–1/2

Question 4

A thin metal plate is exposed to solar radiation. The air and the surroundings are at 30 °C. The heat transfer coefficient by free convection from the upper surface of the plate is 17.4 W/m2K. The plate has an absorptivity of 0.9 at solar wavelength and an emissivity of 0.1 at the long wavelength. Neglecting any heat loss from the lower surface, determine the incident solar radiation intensity in kW/m2, if the measured equilibrium temperature of the plate is 50 °C. Stefan Boltzmann constant is 5.67×10-8 W/m2K4.

  • A0.452
  • B0.76
  • C5.45
  • D0.402

Question 5

What will be the heat transfer rate through the slab as shown, if Q, T1 and T2 are given?

  • AQ = TL – TR / R = (TL – TR) / (R1 + R2)
  • BQ = TL + TR / R = (TL – TR) / (R1 + R2)
  • CQ = TL – TR / R = (TL + TR) / (R1 + R2)
  • DQ = TL + TR / R = (TL + TR) / (R1 + R2)

Question 6

A solid sphere of radius r1 = 20 mm is placed concentrically inside a hollow sphere of radius r2 = 30 mm as shown in the figure.

The view factor F21 for radiation heat transfer is

  • A2/3
  • B4/9
  • C8/27
  • D9/4
Categories: Exams

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