Coulomb's constant k has the value

Coulomb's constant k has the value

• A. 1.0 x 10^9 N m^2/C^2
• B. 8.99 x 10^9 N m^2/C^2
• C. 9.0 x 10^8 N m^2/C^2
• D. 9.0 x 10^9 N m^2/C^2

Answer: (D)

Coulomb’s constant k comes from k = 1/(4π ε0). In SI units, ε0 is about 8.854 × 10^-12 C^2/(N·m^2), so k ≈ 1 / (4π × 8.854 × 10^-12) ≈ 8.99 × 10^9 N·m^2/C^2. That means the precise value is around 8.9875 × 10^9, and in many problems it’s rounded to a convenient figure. Using 9.0 × 10^9 N·m^2/C^2 is the standard rounded form, which is why that option is considered the best match. The other numbers are either too small by roughly an order of magnitude or do not reflect the typical SI rounding of k.

Coulomb’s constant k comes from k = 1/(4π ε0). In SI units, ε0 is about 8.854 × 10^-12 C^2/(N·m^2), so k ≈ 1 / (4π × 8.854 × 10^-12) ≈ 8.99 × 10^9 N·m^2/C^2. That means the precise value is around 8.9875 × 10^9, and in many problems it’s rounded to a convenient figure. Using 9.0 × 10^9 N·m^2/C^2 is the standard rounded form, which is why that option is considered the best match. The other numbers are either too small by roughly an order of magnitude or do not reflect the typical SI rounding of k.