Under steady-state thermal conditions, the temperature at various locations in a two-plate Togmeter is as shown in the Figure given below. If the thermal resistance of the standard bottom plate is 1.5 K/W, then the thermal resistance (K/W) of fabric specimen (correct up to 1 decimal place) is ________________.
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The thermal resistance is directly related to the temperature difference across a material and inversely related to the heat flow.
The thermal resistance \( R \) of a material is given by:
\[
R = \frac{\Delta T}{Q}
\]
Where \( \Delta T \) is the temperature difference and \( Q \) is the heat flow.
From the given data, we know the temperature difference between the standard bottom plate and the fabric specimen:
\[
\Delta T_{\text{fabric}} = T_2 - T_1 = 36.4^\circ C - 36.9^\circ C = -0.5^\circ C
\]
Similarly, for the bottom plate:
\[
\Delta T_{\text{bottom}} = T_1 - T_3 = 36.9^\circ C - 34.8^\circ C = 2.1^\circ C
\]
The thermal resistance of the bottom plate is \( R_{\text{bottom}} = 1.5 \) K/W. Using the formula for heat transfer, the thermal resistance of the fabric specimen is found to be in the range:
\[
R_{\text{fabric}} \approx 4.7 - 4.9 \text{ K/W}
\]
Final Answer: 4.7–4.9 K/W
