What is the time lapse between seeing a lightning strike and hearing the thunder if the lightning flash is 45 km away? The speed of light waves in air is 3 × 108 m/s and the speed of sound waves in air is 333 m/s. Answer in units of s.
Since the lightning flash & thunder are 45 =Km. away, or 45,000 meters away. But since sound travels at 333 m/s, then by the time it gets to your ear would be 45,000/333=135.14 seconds, or about 2 minutes and 15 seconds before you hear it. You will see the light flash almost instantaniously, because 45 Km from you, it will only takes it: 1/((3 x 10^8)/45000)=1/6,667 of a second to reach your eye.
