Question

Match the LIST-I with LIST-II:

• A. A-II, B-III, C-I, D-IV
• B. A-III, B-IV, C-II, D-I
• C. A-IV, B-III, C-I, D-II
• D. A-I, B-II, C-IV, D-III

Hint:

To distinguish modes: Conduction is through solids; Convection involves fluid motion; Radiation happens through a vacuum or transparent medium. Heat sinks are designed to use conduction to spread heat and convection to remove it!

Answer 1

The Correct Option is C

Concept: Heat transfer occurs through three primary modes: conduction, convection, and radiation. Many real-world engineering problems involve a combination of these modes or the dominance of one specific type depending on the environment.

Step 1: Match A (Boiling Water).
When water boils in an open vessel, the movement of the fluid is driven by density differences caused by temperature gradients. This is a classic example of Dominant natural convection (IV), specifically phase-change convection.

Step 2: Match B (Earth-Atmosphere Exchange).
At night, the earth cools down by emitting energy into the atmosphere and space. This exchange occurs without a medium for conduction or significant bulk fluid movement, making it primarily Thermal radiation (III).

Step 3: Match C (Furnace Wall).
A furnace wall is a stationary solid barrier. Heat travels from the hot inner surface to the cooler outer surface through the material. If the wall is large, this is analyzed as steady-state Conduction in one dimension (I).

Step 4: Match D (Heat Sink).
A heat sink transfers heat from a component via conduction through its fins, which is then carried away by the surrounding air. This is a case where Conduction and convection occur simultaneously (II) to maximize cooling.