Heat in a liquid is transferred by :

Options

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

Answer

To solve the question "Heat in a liquid is transferred by:", we will analyze the different methods of heat transfer and determine which one is applicable to liquids.

### Step-by-Step Solution:

1. **Understand the Methods of Heat Transfer**:
- There are three main methods of heat transfer: conduction, convection, and radiation.
- **Conduction**: This is the transfer of heat through direct contact between materials. It primarily occurs in solids where particles are closely packed.
- **Convection**: This is the transfer of heat through the movement of fluids (liquids and gases). It occurs when warmer parts of a liquid rise and cooler parts sink, creating a circulation pattern.
- **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.

2. **Identify the State of Matter**:
- The question specifies that we are dealing with a liquid. Liquids are considered fluids, which means they can flow and move.

3. **Determine the Relevant Heat Transfer Method for Liquids**:
- Since liquids can flow, the primary method of heat transfer in liquids is convection. As the liquid is heated, it becomes less dense and rises, while cooler, denser liquid sinks, creating a convection current.

4. **Eliminate Other Options**:
- **Conduction**: While conduction can occur in liquids, it is not the primary method of heat transfer in them.
- **Radiation**: This method does not require a medium and is not specific to liquids.
- **Conduction and Radiation**: This option includes conduction, which is not the main method for heat transfer in liquids.

5. **Conclusion**:
- The correct answer to the question is **B. Convection**, as this is the primary method of heat transfer in liquids.

### Final Answer:
Heat in a liquid is transferred by **B. Convection**.