- What is the phenomenon of sound reflecting back and being heard again?
- Answer: Echo
- Explanation: An echo occurs when sound waves reflect off a distant surface and are heard separately from the original sound.
- What is the minimum time gap required between the original sound and its echo?
- Answer: 0.1s
- Explanation: The human brain retains sound for 0.1 seconds; to hear a distinct echo, the reflected sound must be delayed by at least this time.
- What is the minimum distance required for an echo to be heard at 22°C?
- Answer: 17.2m
- Explanation: The reflecting surface must be at least 17.2 meters away to allow the sound to travel to the surface and return in 0.1 seconds.
- What is the speed of sound in air at 22°C used for echo calculations?
- Answer: 344 m/s
- Explanation: The speed of sound in air varies with temperature, and at 22°C, it is considered 344 m/s for echo calculations.
- What natural phenomenon is caused by multiple echoes from clouds and the ground?
- Answer: Thunder
- Explanation: Rolling thunder is caused by successive reflections of sound from clouds and land, creating multiple echoes.
- What type of surfaces are best for producing echoes?
- Answer: Hard
- Explanation: Hard surfaces like walls, mountains, and large buildings reflect sound efficiently, making echoes more distinct.
- What happens to an echo when the temperature increases?
- Answer: Distance changes
- Explanation: Since the speed of sound increases with temperature, the minimum distance for an echo also changes.
- What type of sound reflection results in multiple echoes?
- Answer: Successive
- Explanation: Echoes can be heard multiple times if the sound reflects off different surfaces successively.
- What device uses sound reflection to measure distances, such as ocean depth?
- Answer: Sonar
- Explanation: SONAR (Sound Navigation and Ranging) sends sound pulses underwater and measures the reflected echoes.
- What is the phenomenon where sound persists due to repeated reflections in a hall?
- Answer: Reverberation
- Explanation: Reverberation is the persistence of sound due to multiple reflections, which can make speech unclear in large halls
