How fast does light travel in a vacuum in kilometers per second?

Light travels in a vacuum at an incredibly high speed of approximately 300,000 kilometers per second. This speed is a fundamental constant of nature and is denoted by the symbol 'c' in physics. It plays a crucial role in various theories and equations, such as Einstein's theory of relativity, which asserts that nothing can travel faster than light in a vacuum.

The speed of light is vital for understanding electromagnetic radiation and is integral to concepts of space and time in physics. Its value significantly influences the behavior of light and its interaction with matter, leading to numerous applications in technology and science, from telecommunications to astronomy.

The other values provided do not accurately represent the established speed of light in a vacuum. 150,000 kilometers per second and 200,000 kilometers per second are notably lower than the actual speed, while 400,000 kilometers per second exceeds the known maximum speed of light. Thus, recognizing 300,000 kilometers per second as the correct answer aligns perfectly with the scientific understanding of light propagation in a vacuum.