The vital capacity of lungs of an average human is

Options

A. 1200 ml
B. 2400 ml
C. 4000 ml
D. 6000 ml

Answer

To determine the vital capacity of the lungs of an average human, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Vital Capacity**:
- Vital capacity (VC) is defined as the maximum amount of air a person can exhale after a maximum inhalation. It includes the air that can be inhaled and exhaled with effort.

2. **Components of Vital Capacity**:
- Vital capacity can be calculated using the following formula:
\[ VC = IRV + ERV + TV \]
- Where:
- **IRV** (Inspiratory Reserve Volume): The additional air that can be inhaled after a normal inhalation.
- **ERV** (Expiratory Reserve Volume): The additional air that can be exhaled after a normal exhalation.
- **TV** (Tidal Volume): The amount of air inhaled or exhaled during normal breathing.

3. **Average Values**:
- The average values for these components in an adult human are approximately:
- IRV: 3000 ml
- ERV: 1100 ml
- TV: 500 ml

4. **Calculating Vital Capacity**:
- Plugging in the average values into the formula:
\[ VC = 3000 \, \text{ml} + 1100 \, \text{ml} + 500 \, \text{ml} = 4600 \, \text{ml} \]
- Therefore, the vital capacity of an average human is around 4600 ml.

5. **Selecting the Correct Option**:
- The options provided were:
- 1200 ml
- 2400 ml
- 4000 ml
- 6000 ml
- Since 4600 ml falls between 4000 ml and 6000 ml, the closest average value is **4000 ml**.

### Conclusion:
- The vital capacity of the lungs of an average human is approximately **4000 ml**.