If there is no gravity i.e. acceleration due to gravity is zero then which method of heat transfer is not possible

Options

A. Radiation
B. Natural convection
C. Conduction
D. All of these

Answer

To solve the question, we need to identify the method of heat transfer that is dependent on gravity. There are three primary methods of heat transfer: conduction, convection, and radiation. Let's analyze each method step by step.

### Step 1: Understand the three methods of heat transfer
1. **Conduction**: This is the transfer of heat through a material without the movement of the material itself. It occurs due to the interaction of molecules and does not require gravity.

2. **Convection**: This method involves the transfer of heat by the physical movement of a fluid (liquid or gas). In natural convection, warmer, less dense portions of the fluid rise while cooler, denser portions sink. This process is heavily influenced by gravity.

3. **Radiation**: This is the transfer of heat in the form of electromagnetic waves. It does not require a medium and can occur in a vacuum. Thus, it is independent of gravity.

### Step 2: Identify the method dependent on gravity
From our analysis:
- **Conduction** does not depend on gravity.
- **Radiation** does not depend on gravity.
- **Convection**, specifically natural convection, relies on gravity to facilitate the movement of fluid based on temperature differences.

### Conclusion
Since natural convection is the only method of heat transfer that relies on gravity, we conclude that if there is no gravity (i.e., acceleration due to gravity is zero), then **natural convection is not possible**.

### Final Answer
The method of heat transfer that is not possible if there is no gravity is **natural convection**.

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