Metric prefixes and powers of ten: Which SI prefix corresponds exactly to 10^−9?

Introduction / Context:
Fluent use of SI prefixes accelerates reading schematics, data sheets, and oscilloscope settings. In electronics, dimensions like nanoseconds, nanofarads, and nanometers appear frequently, so mapping prefixes to powers of ten must be automatic.

Given Data / Assumptions:

• The SI system defines fixed prefixes for decimal powers of 10.
• We compare nano, micro, kilo, and mega.
• We want the exact match for 10^−9.

Concept / Approach:
Know the core ladder around unity: micro = 10^−6, nano = 10^−9, pico = 10^−12. On the larger side: kilo = 10^3, mega = 10^6, giga = 10^9. With this mental map, you can quickly scale quantities and convert units without repeatedly writing exponents.

Step-by-Step Solution:

Verification / Alternative check:
Check with common terms: 1 ns = 10^−9 s; 1 nm = 10^−9 m. These everyday engineering quantities confirm the mapping.

Why Other Options Are Wrong:

• Micro: Three orders larger than nano (10^−6).
• Kilo/Mega: Positive powers for larger quantities, not submultiples.

Common Pitfalls:
Confusing the Greek letters µ (micro) and n (nano) in component labels or mixing up m (milli, 10^−3) with M (mega, 10^6).

Final Answer:
Nano