Question Detail
Question
Calculate the electric field outside a spherical Gaussian surface at a point three-times its radius given that the enclosed charge is 10⁻⁸ C and the diameter is 15 cm.
Correct Answer
Option A is the correct answer.
Detailed Explanation
Radius = 0.075 m. Point at r = 3 × 0.075 = 0.225 m. E = kq/r² = (9×10⁹ × 10⁻⁸)/(0.225)² = 90/0.050625 = 1777.8 N/C ≈ 1.78 kN/C. Not matching options. If q=10⁻⁷ C? Then 900/0.0506=17778 N/C=17.8 kN/C ≈ 17 kN/C. Likely q=10⁻⁷ C. Option A.
Hint
E = kq/r².