Question

calculate the rate of heat flow through a glass window 2.0m×1.5m area and 3.2 mm thick. If the temperature of the inner and outer surfaces are 15°C and 14°C respectively.
[K for glass= 0.84 w/m/k]​

Answer 1

Answer:

The rate of heat flow per unit time is 787.5 kelvin per sec .

Explanation:

Given as :

The Area of glass window = 2 m × 1.5 m

i,e A = 3 m²

The thickness of window = l = 3.2 mm = 0.0032 m

The inner temperature = $T_1$ = 15° c

The outer temperature = $T_2$ = 14° c

k for glass = 0.84 w/m/k

Let The rate of heat flow per unit time = Q kelvin per sec

According to question

$\dfrac{\Delta Q}{\Delta t}$ = k A × $\dfrac{T_1 - T_2}{l}$

i.e $\dfrac{\Delta Q}{\Delta t}$ = 0.84 × 3 × $\dfrac{15 - 14}{0.0032}$

Or, $\dfrac{\Delta Q}{\Delta t}$ = 2.52 × $\dfrac{1}{0.0032}$

Or, $\dfrac{\Delta Q}{\Delta t}$ = 787.5  k/s

So, The rate of heat flow per unit time = Q = 787.5 kelvin per sec

Hence, The rate of heat flow per unit time is 787.5 kelvin per sec . Answer