Question

The thickness of a metallic plate is $0.4cm$. The temperature between its two surfaces is ${20}^{\circ }C$. The quantity of heat flowing per second is $50$ calories from $5c{m}^2$ area. The coefficient of thermal conductivity (in CGS system) will be

• A. $0.2$
• B. $0.3$
• C. $0.4$
• D. $0.5$

Answer 1

The correct option is A $0.2$

We know that
$\frac{Q}{T}=\frac{KA\left(△\theta \right)}{l}$
$50=\frac{5\times 20K}{0.4}$
or $K=\frac{50\times 0.4}{5\times 20}=0.2$.