問66
頻出度★★☆
値の小さな数や大きな数を分かりやすく表現するために, 接頭語が用いられる。例えば, 10⁻³と10³を表すのに, それぞれ “m” と “k” が用いられる。10⁻⁹と10⁹を表すのに用いられる接頭語はどれか。
平成31年度 春期 ITパスポート試験 問66
テクノロジ系基礎理論 › 情報に関する理論
This question's explanation and your answers so far.
解説
問 66
- ア
正解 In the International System of Units (SI), prefixes are defined as symbols that represent powers of 10. On the negative-exponent side: 10⁻³＝milli “m”, 10⁻⁶＝micro “μ”, 10⁻⁹＝nano “n”, 10⁻¹²＝pico “p”. On the positive-exponent side: 10³＝kilo “k”, 10⁶＝mega “M”, 10⁹＝giga “G”, 10¹²＝tera “T”. Therefore, 10⁻⁹ is represented by nano “n” and 10⁹ by giga “G”, so the correct combination is “n and G”＝ア.
Incorrectイ
Writing 10⁻⁹ as “n” is correct, but “M” (mega) is the prefix for 10⁶ and does not correspond to 10⁹. Since 10⁹ is “G” (giga), this is wrong.
Incorrectウ
Writing 10⁹ as “G” is correct, but “p” (pico) is the prefix for 10⁻¹² and does not correspond to 10⁻⁹. Since 10⁻⁹ is “n” (nano), this is wrong.
Incorrectエ
“p” is the prefix for 10⁻¹² and “M” for 10⁶; neither corresponds to 10⁻⁹ or 10⁹. The correct answer is “n” and “G”, so this is wrong.
ここがポイント
- Correspondence between SI prefixes and powers of 10: on the small side m(10⁻³)→μ(10⁻⁶)→n(10⁻⁹)→p(10⁻¹²), and on the large side k(10³)→M(10⁶)→G(10⁹)→T(10¹²), advancing one step every 3 orders of magnitude.
- Watch out for confusing the symbols: n (nano) and p (pico) differ by 3 orders of magnitude, as do M (mega) and G (giga); count the exponents correctly before matching.