Question

Composite cylindrical wall is composed of two materials of thermal conductivity ka and kb, which are separated by a very thin, electric resistance

Answer 1

The rate of heat conduction through a composite cylindrical wall and a window can be determined using the formula: Q = (k * A * △T) / d. By comparing the rates of heat conduction for the wall and the window, we can determine which material conducts heat more efficiently.

Step-by-step explanation:

The rate of heat conduction can be determined using the formula:

Q = (k * A * △T) / d

where Q is the rate of heat conduction, k is the thermal conductivity, A is the area, △T is the temperature difference, and d is the thickness of the material.

For the first scenario, the wall with a thermal conductivity twice that of glass wool, let's assume the thermal conductivity of glass wool is ka. So, the thermal conductivity of the wall is 2 * ka. The thickness of the wall is 13.0 cm and the area is 10.0 m². Since the temperature difference is the same for both scenarios, we can calculate the rate of heat conduction for the wall.

For the second scenario, the window with a thickness of 0.750 cm and an area of 2.00 m², we can calculate the rate of heat conduction using the given formulas and values.

By comparing the two rates of heat conduction, we can determine which material conducts heat more efficiently.

Answer 2

It is simply a cylindrical resistance network labeled appropriatelyand including a generation input at the heater strip. Is a summing of the conduction from both sides of theheater and setting them equal to the heater power: