A person has exhaled forcefully. The amount of air present in his lungs is

Options

A. 0 litres
B. 3 litres
C. 1.2 litres
D. 0.5 litres

Answer

To solve the question regarding the amount of air present in a person's lungs after they have forcefully exhaled, we will follow these steps:

### Step 1: Understand Lung Capacities
First, we need to understand the different lung capacities and volumes. The primary lung volumes include:
- **Tidal Volume (TV)**: The amount of air inhaled or exhaled during normal breathing, approximately 500 ml.
- **Inspiratory Reserve Volume (IRV)**: The additional air that can be inhaled after a normal inhalation, around 300 ml.
- **Expiratory Reserve Volume (ERV)**: The additional air that can be exhaled after a normal exhalation, approximately 1.2 liters.
- **Residual Volume (RV)**: The amount of air that remains in the lungs after maximum exhalation, which cannot be expelled, approximately 1.2 liters for males and slightly less for females (around 1.1 liters).

### Step 2: Identify the Relevant Volume
The question specifically asks for the amount of air present in the lungs after a forceful exhalation. After forceful exhalation, the volume of air that remains in the lungs is known as the **Residual Volume (RV)**.

### Step 3: Determine the Value of Residual Volume
From our understanding, the average residual volume in healthy males is about **1.2 liters**. This is the volume that remains in the lungs even after the person has exhaled forcefully.

### Step 4: Choose the Correct Option
Given the options:
1. 0L
2. 3L
3. 1.2L
4. 0.5L

The correct answer is **Option 3: 1.2L**, as this represents the residual volume remaining in the lungs after forceful exhalation.

### Conclusion
Thus, the amount of air present in the lungs after a person has forcefully exhaled is **1.2 liters**.

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