Final answer:
The velocity of neutrons in a nuclear reactor is less than the speed of light, as no object with mass can exceed or reach this universal speed limit according to the theory of relativity.
Step-by-step explanation:
The velocity of neutrons in a nuclear reactor is significantly less than the speed of light. According to the principles of physics, specifically the theory of relativity postulated by Albert Einstein, no object with mass can travel at or above the speed of light in a vacuum (c), which is approximately 3.00×108 m/s. Neutrons, being massive particles, therefore have velocities much slower than the speed of light. For example, experiments are sometimes conducted with ultracold neutrons at velocities as low as 1.00 m/s, which is a speed humans can easily perceive. On the other end of the spectrum, neutrons in a reactor may have velocities on the order of 103 to 105 m/s, which, while fast, are still well below the speed of light. Hence, the correct answer to the given question is option 3: Less than the speed of light.