which of the following cannot be measured by spirometer?
(i)FRC. (ii)RV (iii)TLC

Options

A. only (i)
B. (i),(ii) & (iii)
C. only (ii) &(iii)
D. only(i) &(iii)

Answer

To determine which of the following cannot be measured by a spirometer, let's analyze each option step by step:

1. **Understanding Spirometer**:
- A spirometer is an instrument used to measure the volume of air inhaled and exhaled by the lungs. It helps in assessing lung function by measuring various lung volumes and capacities.

2. **Analyzing FRC (Functional Residual Capacity)**:
- FRC is the volume of air remaining in the lungs after a normal expiration. It includes both the residual volume (RV) and the expiratory reserve volume (ERV).
- A spirometer cannot measure FRC directly because it cannot measure the residual volume (RV), which is a component of FRC.

3. **Analyzing RV (Residual Volume)**:
- RV is the amount of air that remains in the lungs after a forceful expiration.
- Since a spirometer measures only the air that is actively inhaled or exhaled and cannot measure the air that remains in the lungs after expiration, RV cannot be measured by a spirometer.

4. **Analyzing TLC (Total Lung Capacity)**:
- TLC is the total volume of air in the lungs after a maximum inhalation. It is the sum of all lung volumes, including tidal volume (TV), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), and residual volume (RV).
- As with FRC and RV, since a spirometer cannot measure the residual volume, it also cannot measure the total lung capacity.

5. **Conclusion**:
- Since a spirometer cannot measure FRC, RV, or TLC, the answer to the question is that all three options cannot be measured by a spirometer.

**Final Answer**: (i) FRC, (ii) RV, (iii) TLC - All three cannot be measured by a spirometer.

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