Heat Transfer

Step 1: Use the heat conduction formula.
The heat flow through a rod is given by Fourier’s Law: where: - is the coefficient of thermal conductivity, - is the cross-sectional area, - is the temperature difference, and - is the length of the rod.

Step 2: Calculate the Temperature Gradient.
The temperature gradient is given by: Substitute the given values: Thus, the temperature gradient is:

Step 1: Understanding the Concept:
Mirror formula: . For convex mirror, is positive, is negative.
Step 2: Detailed Explanation:
Given , .

. Image is virtual, behind the mirror.
Step 3: Final Answer:
Thus, image distance = .

Concept: Modes of heat transfer:
• Conduction (in solids)
• Convection (in fluids)
• Radiation (no medium required)

Step 1:Analyze each option.

• (A) Sea and land breeze → Convection (air movement)
• (B) Boiling of water → Convection (liquid currents)
• (D) Heating air around furnace → Convection

Step 2:Remaining option.

• (C) Warming of glass bulb due to filament → mainly radiation Conclusion : C