What is the SI unit of pressure?

Appeared in: DSSSB - 29 August 2019 (Shift-2)

Explanation

Pascal (Pa) is the standard international (SI) unit of pressure.
Pressure is defined as force applied per unit area (P = F/A).
One Pascal is equivalent to one Newton of force applied over an area of one square meter (1 Pa = 1 N/m²).

Option A: Joule (J) is the SI unit of energy or work, not pressure.
Option C: Ampere (A) is the SI unit of electric current, not pressure.
Option D: Newton (N) is the SI unit of force. Pressure is force distributed over an area, not force itself.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain SI unit of pressure as background academic context rather than a clinical decision trigger.
While Pascal is the scientific standard, clinical pressure measurements like blood pressure are almost universally recorded in millimeters of mercury (mmHg).
Other non-SI units like centimeters of water (cmH₂O) are used for measuring central venous pressure (CVP) and intracranial pressure (ICP).
Understanding the base SI unit is crucial for converting between different units and for interpreting research that uses standard scientific notation.

How to Approach the Question

First, identify the key terms in the question: 'SI unit' and 'pressure'.
This is a factual recall question from general science, which is often part of nursing entrance exams.
Recall the definition of pressure: Force per unit Area (P = F/A).
Consider the units for force (Newton) and area (m²). The unit for pressure is therefore N/m².
Recognize that the specific name for N/m² is Pascal (Pa).
Evaluate the other options to confirm they are incorrect: Joule (energy), Ampere (current), and Newton (force).

Concept Tested & Keywords

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Practise the full DSSSB - 29 August 2019 (Shift-2)

Attempt every question from this paper in a timed mock, then review the full solution for each one.