Question

Heat flows through a rod of length 1 m and area 1 m$^2$. Temperature difference = 10 K. If thermal conductivity = 5 W/mK, heat flow per second is:

• A. 10 W
• B. 25 W
• C. 50 W
• D. 100 W

Hint:

Thermal conductivity is an intrinsic property. In problems like this where length and area are both $1$, the heat flow per second numerically equals the product of the thermal conductivity and the temperature difference ($k \times \Delta T$).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Conduction is the transfer of heat through solids. The rate depends on dimensions and material properties.
Step 2: Key Formula or Approach:
Fourier's Law: \[ H = \frac{kA \Delta T}{L} \]
Step 3: Detailed Explanation:
\(k = 5\), \(A = 1\), \(\Delta T = 10\), \(L = 1\).
\[ H = \frac{5 \times 1 \times 10}{1} = 50 \text{ Watts} \]
Step 4: Final Answer:
Heat flow is 50 W.