Water is used in car radiators as coolant because

Options

A. of its lower density
B. it is easily available
C. it is cheap
D. it has high specific heat

Explanation

To solve the question "Water is used in car radiators as coolant because:", we will analyze the options provided and determine the most suitable reason based on the properties of water.

### Step-by-Step Solution:

1. **Understanding the Role of Coolants**:
- Coolants are substances that absorb heat from the engine and help maintain optimal operating temperatures. They need to have certain properties to be effective.

2. **Evaluating the Options**:
- **Option 1: Lower Density**: While density can affect the flow and circulation in the radiator, it is not the primary reason for using water as a coolant.
- **Option 2: Easily Available**: Water is indeed abundant and easily accessible, but this alone does not justify its use as a coolant.
- **Option 3: Cheap**: Water is inexpensive, which is beneficial, but again, cost alone does not make it an effective coolant.
- **Option 4: High Specific Heat Capacity**: Water has a high specific heat capacity (approximately 4184 J/kg·K), meaning it can absorb a significant amount of heat with only a small increase in temperature. This property is crucial for maintaining engine temperatures.

3. **Conclusion**:
- The most compelling reason for using water in car radiators as a coolant is its high specific heat capacity. This allows it to effectively absorb and dissipate heat, preventing the engine from overheating.

### Final Answer:
Water is used in car radiators as coolant because it has a high specific heat capacity.