E-PolyLearning

Discussion Forum

Que. The thermal resistance for heat conduction through a hollow sphere of inner radius r1 and outer radius r2 is
a. r₂ – r₁/4πk r₁r₂
b. r₂ /4πk r₁r₂
c. r₁/4πk r₁r₂
d. 4πk r₁r₂
Correct Answer:r₂ – r₁/4πk r₁r₂
Confused About the Answer? Ask fellow aspirants for Details Here
Already Know Explanation? Add it Here to help others.

More Questions Like this:

Let us say thermal conductivity of a wall is governed by the relation k = k0 (1 + α t). In that case the temperature at the mid-plane of the heat conducting wall would be
The annealing furnace for continuous bar stock is open at the ends and has interior dimensions of 0.6 m * 0.6 m * 1.5 m long with a wall 0.3 m thick all around. Calculate the shape factor for the furnace?
For a prescribed temperature difference, bodies with the same shape factor will allow heat conduction proportional to
The temperature distribution in a large thin plate with uniform surface temperature will be
(Assume steady state condition)
“All the factors relating to geometry of the sections are grouped together into a multiple constant called the shape factor” True or false
A stainless steel tube with inner diameter₁2 mm, thickness 0.2 mm and length 50n cm is heated electrically. The entire 15 k W of heat energy generated in the tube is transferred through its outer surface. Find the intensity of current flow
The thermal resistance for heat conduction through a spherical wall is
For the same amount of fabrication material and same inside capacity, the heat loss is lowest in
The oven of an electric store, of total outside surface area 2.9 m² dissipates electric energy at the rate of 600 W. The surrounding room air is at 20 degree Celsius and the surface coefficient of heat transfer between the room air and the surface of the oven is estimated to be 11.35 W/m² degree. Determine the average steady state temperature of the outside surface of the store
A cylindrical cement tube of radii 0.05 cm and 1.0 cm has a wire embedded into it along its axis. To maintain a steady temperature difference of 120 degree Celsius between the inner and outer surfaces, a current of 5 ampere is made to flow in the wire. Find the amount of heat generated per meter length. Take resistance of wire equal to 0.1 ohm per cm of length
The rate of convective heat transfer between a solid boundary and adjacent fluid is given by
A composite wall is made of two layers of thickness δ₁ and δ₂ having thermal conductivities k and 2k and equal surface area normal to the direction of heat flow. The outer surface of composite wall are at 100 degree Celsius and 200 degree Celsius. The minimum surface temperature at the junction is 150 degree Celsius. What will be the ratio of wall thickness?
The mean thermal conductivity evaluated at the arithmetic mean temperature is represented by
If β is greater than zero, then choose the correct statement with respect to given relation
k = k0 (1 +β t)
The value of critical radius in case of cylindrical hollow object is
A homogeneous wall of area A and thickness δ has left and right hand surface temperatures of 0 degree Celsius and 40 degree Celsius. Determine the temperature at the center of the wall
The rate of heat conduction through a cylindrical tube is usually expressed as
“If β is less than zero, then with respect to the relation k = k0 (1 + β t), conductivity depends on surface area”. True or false
Shape factor for sphere is
The heat flow equation through a cylinder of inner radius r1 and outer radius r2 is desired to be written in the same form as that for heat flow through a plane wall. For wall thickness (r₂-r₁) the area will be

View All Questions on: Steady State Conduction

Management and Accounting

Human Resource Management Marketing and Marketing Management Financial Management and Financial Markets Cost Accounting Business Statistics