What unit of speed is defined as one nautical mile per hour?

• A. Mile per Hour
• B. Kilometer per Hour
• C. Knot
• D. Light-year

Answer: (C)

In navigation, speed is tied to nautical miles and hours, so a knot is defined as one nautical mile per hour. One nautical mile is exactly 1/60 of a degree of latitude, about 1,852 meters, and traveling at 1 knot means you cover one nautical mile each hour. This unit is standard for ships and aircraft because it aligns with charts and navigation measurements that use nautical miles. The other options are different concepts: miles per hour uses land miles, kilometers per hour uses metric kilometers, and a light-year is a distance unit for how far light travels in a year, not a speed unit.