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4 years ago

12

Given the following materials and their corresponding thermal conductivity values, list them in order from most conductive to le

ast conductive.Sheet Rock: k = 0.43 W/(m*K)Masonite: k = 0.047 W/(m*K)Glass: k = 0.72 W/(m*K)Lexan: k = 0.19 W/(m*K)b) Given the following information, calculate the thermal conductivity using Fourier's Equation.q = 100 WA = 8 m^2ATΔT= 10L = 7 m

1 answer:

Wittaler [7]4 years ago

3 0

Answer:

1) Glass

2) Rock sheet

3) Lexan

4) Masonite

b) k = 8.75 W/m.K

Explanation:

Given:

The thermal conductivity of certain materials as follows:

-Sheet Rock: k = 0.43 W/(m*K)

-Masonite: k = 0.047 W/(m*K)

-Glass: k = 0.72 W/(m*K)

-Lexan: k = 0.19 W/(m*K)

Data Given:

- Q = 100 W

- A = 8 m^2

- dT = 10 C

- L = 7 m

Find:

a) list the materials in order from most conductive to least conductive

b) calculate the thermal conductivity using Fourier's Equation

Solution:

- We know from Fourier's Law the relation between Heat transfer and thermal conductivity as follows:

Q = k*A*dT / L

- From the relation above we can see that rate of heat transfer is directly proportional to thermal conductivity k.

- Hence, the list in order of decreasing conductivity is as follows:

- The list of materials in the decreasing order of thermal conductivity k is:

1) Glass k = 0.72 W/m.K

2) Rock sheet k = 0.43 W/m.K

3) Lexan k = 0.19 W/m.K

4) Masonite k = 0.047 W/m.K

- Use the relation given above we can compute the thermal conductivity k with the given data:

k = Q*L / (A*dT)

k = (100 W * 7 m) / (8 m^2*10 C)

k = 8.75 W/m.K

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