The speed of sound in air is 60 m/s. How far from the centre of a storm is an observer who hears a thunder clap 4s after the flash of the lightning?

1. Analyze the question

We are given the speed of sound ($v$) and the time interval ($t$) between seeing the lightning flash and hearing the thunder. We need to calculate the distance ($d$) from the observer to the source of the storm.

2. Explain the concept

In physics, the relationship between distance, speed, and time is defined by the formula:

Since light travels almost instantaneously compared to sound, the time delay between the flash and the sound is effectively the time it takes for the sound wave to travel from the storm to the observer.

3. Show the solution

• Given: • Speed of sound ($v$) = $60 \text{ m/s}$ • Time ($t$) = $4 \text{ s}$

• Calculation: • $d = v \times t$ • $d = 60 \text{ m/s} \times 4 \text{ s}$ • $d = 240 \text{ m}$

4. Identify the answer

Based on the calculation, the distance is 240 meters. This corresponds to option D.

(Note: In real-world physics, the speed of sound in air is typically around 330–340 m/s. However, for the purpose of this specific JAMB question, we must use the value provided in the prompt, which is 60 m/s.)

5. Tip

When solving speed-distance-time problems, always check your units. If the speed is in m/s and the time is in seconds, your distance will automatically be in meters. If the time were given in minutes, you would need to convert it to seconds first!