To hear a distinct echo, what is the minimum time interval required between the original sound and the echo?

Correct option is B

The correct answer is (b) 0.1 second.
· To hear a distinct echo, the minimum time interval required between the original sound and the reflected sound (echo) must be at least 0.1 second.
· This time interval allows the human ear to distinguish the echo as a separate sound from the original. This is based on the speed of sound in air (approximately 343 meters per second) and the distance sound must travel to create an echo. For a distinct echo, the reflecting surface must be at least 17.2 meters away from the sound source.
Information Booster:
· Speed of Sound: In air, the speed of sound is about 343 meters per second at room temperature.
· Echo Formation: An echo is a reflection of sound that arrives at the listener after a delay. For it to be perceived as distinct, the sound must travel to the reflecting surface and back, covering a significant distance.
· Distance Calculation: Given the speed of sound, the minimum distance for a distinct echo is approximately 17.2 meters (calculated as 343 meters per second multiplied by 0.1 second divided by 2, since the sound travels to the surface and back).