符号、系数前缀和希腊字母

符号

• 𝑐 Speed of light in a vacuum inertial frame: 2.99792458 × 10⁸ m/s ≈ 3 × 10⁸ m/s

• 𝜀 Efficiency; typically 0 ≤ 𝜀 ≤ 1; unitless

• 𝑔 acceleration due to gravity: 9.8 m/s2 or ≈10 m/s²

• h Planck’s constant: 6.626 × 10^-34 J · s

• 𝑘 Boltzmann’s constant: 1.38 × 10^-23 J/K B

• 𝑁 Avogadro’s number: 6.022 × 10²³ particles per mole A

• Δ𝑄 Change in thermal energy, in Joules

• 𝑅_⊕ Radius of Earth: 6,378 km

• 𝑅_⊙ Radius of Sun: 695,700 km

• 𝑟_⊕⊙ Earth–Sun distance (1 AU): 149.6 million km

• 𝜎 Stefan-Boltzmann constant: 5.67 × 10^-8 W/K/m² Δ𝑆 Change in entropy, in J/K

• Δ𝑇 Change in temperature, typically in ◦C or Kelvin (K) Δ𝑊 Change in energy—work performed, in Joules

标度系数前缀

希腊字母和发音