A wall with a cavity consists of two layers o | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(D) In a steady-state condition,the rate of heat flow $H = \frac{kA \Delta T}{L}$ is constant through all layers. Since the area $A$ and thickness $L$

Vedclass · Accepted Answer

Vedclass · Answer

(D) In a steady-state condition,the rate of heat flow $H = \frac{kA \Delta T}{L}$ is constant through all layers. Since the area $A$ and thickness $L$ are the same for all three layers,the temperature drop $\Delta T$ across each layer is inversely proportional to its thermal conductivity $k$ $(\Delta T = \frac{HL}{kA} \propto \frac{1}{k})$.Since the thermal conductivity of brick $(k_b)$ is much greater than that of air $(k_a)$,the temperature drop across the air layer will be much larger than the temperature drop across each brick layer.Therefore,the graph must show a steep linear decrease in temperature across the air layer and a gradual linear decrease across the brick layers. Option $(D)$ correctly represents this behavior.

Similar Questions

$A$ long metallic bar is carrying heat from one of its ends to the other end under steady-state. The variation of temperature $\theta$ along the length $x$ of the bar from its hot end is best described by which of the following figures?

Three rods of the same dimension have thermal conductivities $3K$,$2K$,and $K$. They are arranged as shown in the figure,with their ends at $100^oC$,$50^oC$,and $20^oC$. The temperature of their junction is ......... $^oC$.

If heat conduction in Figure $1$ takes $12 \, sec$,how much time (in $sec$) will it take for the same amount of heat to be conducted in Figure $2$?

$A$ black body radiates maximum energy at wavelength $\lambda$ and its emissive power is $E$. Now, due to a change in the temperature of that body, it radiates maximum energy at wavelength $\frac{2 \lambda}{3}$. At that temperature, the emissive power is:

Vedclass Test Series

Exam Paper Generator

Online Exam Module