(a) Explanation Given info: The test sample is incubated for 24 hours at 37 ∘ C , the heat of fusion is 205 kj / kg , the surface area of panel is 0.409 m 2 , the panel thickness is 4.50 cm , the conductivity is 0.0120 W / m- ° C , the exterior temperature is 23 ° C for 12 hours and 16 ° C for 12 hours. The mass of waxy material is given as, m = Q L f (1) Here, L f is the heat of fusion Q is the total energy lost by conduction in insulation m is the mass of waxy material The total energy lost by conduction through insulation during the 24 hours is given as, Q = P 1 ( 12 h ) + P 2 ( 12 h ) Q = ( P 1 + P 2 ) × ( 12 h ) (2) Here, P 1 is the thermal conductivity at 23 ° C P 2 is the thermal conductivity at 16 ° C The thermal conductivity equation is given as, P = K A ( T H − T C ) L Here, K is the conductivity A is the area of panel L is the thickness of the panel T H is the 24 hour temperature. T C is the temperature at thermal conductivity P 1 and at thermal conductivity P 2 Thermal conductivity at 23 ° C is given as, P 1 = K A ( T H − T C ) L (3) Substitute 37 ° C for T H and 23 ° C for T C in equation (3) to find P 1 , P 1 = K A ( 37 − 23 ) L Thermal conductivity at 16 ° C is given as, P 2 = K A ( T H − T C ) L (4) Substitute 37 ° C for T H and 16 ° C for T C in equation (4) to find P 2 , P 2 = K A ( 37 − 16 ) L Substitute the value of P 1 and P 2 in equation (2) (b) To determine The reason for which the calculation can be done without knowing the mass of test sample.

9th Edition

ISBN: 9781305000988

Author: SERWAY

Publisher: CENGAGE LEARNING (CUSTOM)

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Question

Chapter 20, Problem 20.56P

(a)

To determine

The mass of waxy material that is required to perform the bacteriological test.

(b)

To determine

The reason for which the calculation can be done without knowing the mass of test sample.

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Chapter 20 Solutions

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The mass of waxy material that is required to perform the bacteriological test.

Solution Summary: The author explains the mass of waxy material required to perform the bacteriological test.

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The mass of waxy material that is required to perform the bacteriological test.

The reason for which the calculation can be done without knowing the mass of test sample.

Chapter 20 Solutions