1
GATE ME 2013
MCQ (Single Correct Answer)
+2
-0.6
Two large diffuse gray parallel plates, separated by a small distance, have surface temperatures of $$400$$ $$K$$ and $$300$$ $$K.$$ If the emissivities of the surfaces are $$0.8$$ and the Stefan-Boltzmann constant is $$5.67 \times {10^{ - 8}}$$ $$W/{m^2}{K^4},$$ the net radiation heat exchange rate in $$kW/{m^2}$$ between the two plates is
A
$$0.66$$
B
$$0.79$$
C
$$0.99$$
D
$$3.96$$
2
GATE ME 2012
MCQ (Single Correct Answer)
+2
-0.6
Consider two infinitely long thin concentric tubes of circular cross section as shown in the figure. If $${D_1}$$ and $${D_2}$$ are the diameters of the inner and outer tubes respectively, then the view factor $${F_{22}}$$ is given by GATE ME 2012 Heat Transfer - Radiation Question 14 English
A
$$\left( {{{{D_2}} \over {{D_1}}}} \right) - 1$$
B
Zero
C
$$\left( {{{{D_1}} \over {{D_2}}}} \right)$$
D
$$1 - \left( {{{{D_1}} \over {{D_2}}}} \right)$$
3
GATE ME 2009
MCQ (Single Correct Answer)
+2
-0.6
Radiative heat transfer is intended between the inner surfaces of two very largen isothermal parallel metal plates. While the upper plate (designated as plate $$1$$) is a black surface and is the warmer one being maintained at $${727^ \circ }C,$$ the lower plate (plate $$2$$) is a diffuse and gray surface with an emissivity of $$0.7$$ and is kept at $${27^ \circ }C.$$ Assume that the surfaces are sufficiently large to form a two-surface enclosure and steady state conditions to exist. Stefan Boltzmann constant is given as
$$5.67 \times {10^{ - 8}}\,W/{m^2}{K^4}$$

If plate is also a diffuse gray surface with an emisivity value of $$0.8,$$ the net radiant heat exchange (in $$kW/{m^2}$$) between plate $$1$$ and plate $$2$$

A
$$17.0$$
B
$$19.5$$
C
$$23.0$$
D
$$31.7$$
4
GATE ME 2009
MCQ (Single Correct Answer)
+2
-0.6
Radiative heat transfer is intended between the inner surfaces of two very largen isothermal parallel metal plates. While the upper plate (designated as plate $$1$$) is a black surface and is the warmer one being maintained at $${727^ \circ }C,$$ the lower plate (plate $$2$$) is a diffuse and gray surface with an emissivity of $$0.7$$ and is kept at $${27^ \circ }C.$$ Assume that the surfaces are sufficiently large to form a two-surface enclosure and steady state conditions to exist. Stefan Boltzmann constant is given as
$$5.67 \times {10^{ - 8}}\,W/{m^2}{K^4}$$

The irradiation (in $$kW/{m^2}$$) for the upper plate is

A
$$2.5$$
B
$$3.6$$
C
$$17.0$$
D
$$19.5$$
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