1
GATE ME 2014 Set 3
MCQ (Single Correct Answer)
+1
-0.3
Consider a long cylindrical tube of inner and outer radii, $${r_i}$$ and $${r_0}$$ , respectively, length, $$L$$ and thermal conductivity, $$k.$$ Its inner and outer surfaces are maintained at $${T_i}$$ and $${T_0}$$ , respectively $$\left( {{T_i}\,\,\, > \,\,\,{T_0}} \right).$$ Assuming one-dimensional steady state heat conduction in the radial direction, the thermal resistance in the wall of the tube is
A
$${1 \over {2\pi kL}}\ell n\left( {{{{r_i}} \over {{r_0}}}} \right)$$
B
$${L \over {2\pi {r_i}k}}$$
C
$${L \over {2\pi kL}}\ell n\left( {{{{r_0}} \over {{r_i}}}} \right)$$
D
$${L \over {4\pi kL}}\ell n\left( {{{{r_0}} \over {{r_i}}}} \right)$$
2
GATE ME 2013
MCQ (Single Correct Answer)
+1
-0.3
Consider one-dimensional steady state heat conduction along x-axis $$\left( {0 \le x \le L} \right),$$ through a planewall with the boundary surfaces $$(x=0$$ and $$x=L)$$ maintained at temperatures of $${0^ \circ }C$$ and $${100^ \circ }C$$. Heat is generated uniformly throughout the wall. Choose the CORRECT statement.
A
The direction of heat transfer will be from the surface at 100°C to the surface at $${0^ \circ }C$$.
B
The maximum temperature inside the wall must be greater than $${100^ \circ }C$$.
C
The temperature distribution is linear within the wall.
D
The temperature distribution is symmetric about the mid-plane of the wall.
3
GATE ME 2013
MCQ (Single Correct Answer)
+1
-0.3
Consider one-dimensional steady state heat conduction, without heat generation, in a plane wall; with boundary conditions as shown in the figure below. The conductivity of the wall is given by $$k = {k_0} + bT;$$ where $${k_0}$$ and $$b$$ are positive constants, and $$T$$ is temperature. GATE ME 2013 Heat Transfer - Conduction Question 43 English

As $$x$$ increases, the state temperature gradient $$(dT/dx)$$ will

A
remain constant
B
be zero
C
increase
D
decrease
4
GATE ME 2011
MCQ (Single Correct Answer)
+1
-0.3
A pipe of $$25$$ $$mm$$ outer diameter carries steam. The heat transfer coefficient between the cylinder and surrounding is $$5$$ $$W/{m^2}K.$$ It is propsed to reduce the heat loss from the pipe by adding insulation having a thermal conductivity of $$0.05$$ $$W/mK$$. Which one of the following statements is TRUE?
A
The outer radius of the pipe is equal to the critical radius.
B
The outer radius of the pipe is less than the critical radius.
C
Adding the insulation will reduce the heat loss.
D
Adding the insulation will increase the heat loss.
GATE ME Subjects
Turbo Machinery
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