The speed of light in a vacuum is approximately: A 3 × 10⁶ m/s B 3 × 10⁸ m/s C 3 × 10¹⁰ m/s D 3 × 10⁴ m/s ✓ Correct Answer: Option B Light travels at approximately 3 × 10⁸ m/s (about 300,000 km/s) in a vacuum. Practice ACT Exam Prep Quizzes → Browse All Questions Study Flashcards