Heat from sun reaches us by

Options

A. conduction
B. convection
C. radiation
D. reflection

Answer

To solve the question of how heat from the Sun reaches us, we will analyze the three modes of heat transfer: conduction, convection, and radiation.

### Step-by-Step Solution:

1. **Understanding Heat Transfer Modes**:
- There are three primary modes of heat transfer: conduction, convection, and radiation.
- Conduction requires a medium (solid, liquid, or gas) for heat transfer.
- Convection also requires a medium, typically fluids (liquids and gases), where warmer parts of the fluid rise and cooler parts sink.

**Hint**: Remember that conduction and convection both need a medium to transfer heat.

2. **Analyzing the Environment**:
- The Sun is located in space, which is a vacuum. In a vacuum, there are no particles to facilitate conduction or convection.
- Since there is no medium in space, conduction and convection cannot occur.

**Hint**: Consider the properties of space and how they affect heat transfer.

3. **Identifying the Correct Mode of Heat Transfer**:
- The only mode of heat transfer that does not require a medium is radiation.
- Radiation involves the transfer of heat through electromagnetic waves, which can travel through a vacuum.

**Hint**: Think about how light and heat from the Sun can travel through space without needing air or any other medium.

4. **Conclusion**:
- Therefore, the heat from the Sun reaches us by radiation. This is the correct answer to the question.

**Final Answer**: Heat from the Sun reaches us by radiation.