Which is the value of Planck's constant (m² kg/sec)?

Correct answer: d 6.626 × 10⁻³⁴

Planck's constant h = 6.626 × 10⁻³⁴ m² kg/s.

Why the other options are wrong

• a 6.023 × 10²³: 6.023 × 10²³ is Avogadro's number, from another chapter; h = 6.626 × 10⁻³⁴.
• b 1.673 × 10⁻²⁴: 1.673 × 10⁻²⁴ g is the proton's mass; h = 6.626 × 10⁻³⁴.
• c 9.11 × 10⁻³¹: 9.11 × 10⁻³¹ kg is the electron's mass; h = 6.626 × 10⁻³⁴.