Pressure unit conversion: One bar corresponds to what value in SI base units (N/m^2)?
-
A1 × 10^2 N/m^2
-
B1 × 10^3 N/m^2
-
C1 × 10^4 N/m^2
-
D1 × 10^5 N/m^2
Answer
Correct Answer: 1 × 10^5 N/m^2
Explanation
Introduction / Context:Bar is a convenient non-SI pressure unit frequently used in engineering practice, weather reports, and manufacturer datasheets. Converting between bar and pascals (N/m^2) is necessary for consistency in calculations and standards compliance.
Given Data / Assumptions:
- 1 Pa = 1 N/m^2 by definition.
- Exact definition: 1 bar = 100,000 Pa.
- Atmospheric pressure at sea level ≈ 1.01325 bar (approximate reference).
Concept / Approach:By definition, 1 bar equals 10^5 pascals. This makes bar convenient for approximating atmospheric pressure while maintaining simple powers of ten in engineering problems.
Step-by-Step Solution:
Write conversion: 1 bar = 100,000 Pa.Replace Pa with N/m^2: 1 bar = 1 × 10^5 N/m^2.Select the matching option.Verification / Alternative check:Check sanity: 1 bar ≈ 0.987 atm; 1 atm = 101,325 Pa, close to 10^5 Pa, confirming the order of magnitude.
Why Other Options Are Wrong:
- 10^2, 10^3, 10^4 N/m^2: Off by several orders of magnitude.
Common Pitfalls:Confusing bar with atm or using kPa incorrectly; remember 1 bar = 100 kPa exactly.
Final Answer:1 × 10^5 N/m^2