Question

The thermal conductivity of a material in CGS system is 0.4. In steady state the rate of flow of heat $10cal/s-c{m}^2$, then the thermal gradient will be

• A. ${15}^{o}C/cm$
• B. ${25}^{o}C/cm$
• C. ${50}^{o}C/cm$
• D. ${75}^{o}C/cm$

Answer 1

Answer: (B)

${25}^{o}C/cm$

$\frac{\Delta Q}{\Delta t}=\frac{KA\Delta T}{\Delta x}$
Thermal gradient $\frac{\Delta T}{\Delta x}$ is given by
$\frac{\left(\frac{\Delta Q}{\Delta t}\right)}{KA}=\frac{10}{0.4}={25}^{o}C/cm$