During a thunderstorm, an observer notes that 20 s elapsed between the lightning flash and the sound of the thunder. What is the approximate distance, in miles, from the observer to the lightning?

Question

Quizplus · Accepted Answer

The time between a lightning flash and hearing the thunder can be used to estimate the distance of the lightning strike. Sound travels at approximately 1,125 feet per second (or 340 meters per second) at room temperature and pressure. Therefore, to calculate the distance of the lightning strike in miles, we can use the following formula:

distance = time x speed of sound / 5,280 feet per mile

Plugging in the given values, we get:

distance = 20 s x 1,125 ft/s / 5,280 ft/mi
distance ≈ 4.2 miles

Therefore, the approximate distance from the observer to the lightning is 4 miles, which is closest to choice C (4 mi). The other choices are much too far away given the time delay.

During a Thunderstorm, an Observer Notes That 20 S Elapsed