🔍 Key Concepts

• Relationship between speed, distance, and time (S = D/T). • Approximate speed of radio waves/electromagnetic waves, which is essentially the speed of light in air/vacuum. • Unit conversions: nautical miles to meters and seconds to microseconds.

💭 Think About

• First, recall (or approximate) the speed of radio waves and write it in meters per second. Then convert three nautical miles into meters so distance and speed are in the same units. • Use the formula for time: time = distance ÷ speed. Once you compute the time in seconds, convert that value into microseconds and compare it with the choices. • Estimate roughly: is three nautical miles a very short distance for something traveling at the speed of light? Should the answer be in the range of a few, a few tens, or hundreds of microseconds?

✅ Before You Answer

• Be sure you use 1 nautical mile ≈ 1852 meters when converting distance. • Confirm your unit consistency: both distance and speed must be in meters and meters/second before solving for time. • After converting to microseconds, check whether your answer is on the same order of magnitude as the options (single-digit, tens, or more than 100 microseconds).