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In a room, the reflected sound reaches the ear 0.05 s after its production. Will it produce an echo or reverberation? Justify your answer.
It will produce reverberation rather than an echo. Human hearing requires a minimum time gap of 0.1 seconds between original and reflected sounds to perceive a distinct echo. Because the reflected sound arrives in only 0.05 seconds, the brain cannot separate the two sounds. Instead, the multiple refRead more
It will produce reverberation rather than an echo. Human hearing requires a minimum time gap of 0.1 seconds between original and reflected sounds to perceive a distinct echo. Because the reflected sound arrives in only 0.05 seconds, the brain cannot separate the two sounds. Instead, the multiple reflections blend together, causing the sound to persist as reverberation.
For more NCERT Solutions of Class 9 Science Exploration Chapter 10 Sound Waves Characteristics and Applications Question Answer (2026-27)
https://www.tiwariacademy.com/ncert-solutions/class-9/science/exploration-chapter-10/
See lessGraphs representing two sound waves are given in Fig. 10.30. If the scales on the X and Y axes of the two graphs are the same, which of the two sound waves has (i) greater wavelength and (ii) smaller amplitude?
(i) Greater wavelength: Wave (a) has the greater wavelength because the horizontal distance between two consecutive crests or troughs is visibly larger than in wave (b). (ii) Smaller amplitude: Wave (a) has the smaller amplitude because its maximum vertical displacement of density from the average dRead more
(i) Greater wavelength: Wave (a) has the greater wavelength because the horizontal distance between two consecutive crests or troughs is visibly larger than in wave (b). (ii) Smaller amplitude: Wave (a) has the smaller amplitude because its maximum vertical displacement of density from the average density line is noticeably less than the height of the crests in wave (b).
For more NCERT Solutions of Class 9 Science Exploration Chapter 10 Sound Waves Characteristics and Applications Question Answer (2026-27)
https://www.tiwariacademy.com/ncert-solutions/class-9/science/exploration-chapter-10/
See lessDraw a graph to represent a sound wave for which the density amplitude is 3 units and wavelength is 4 cm.
To represent the wave graphically, plot distance on the x-axis and density on the y-axis with a central dashed line for average density. Draw a periodic sine curve where the crest reaches 3 units above average density and the trough falls 3 units below. The horizontal distance from one crest to theRead more
To represent the wave graphically, plot distance on the x-axis and density on the y-axis with a central dashed line for average density. Draw a periodic sine curve where the crest reaches 3 units above average density and the trough falls 3 units below. The horizontal distance from one crest to the next consecutive crest must measure exactly 4 cm.
For more NCERT Solutions of Class 9 Science Exploration Chapter 10 Sound Waves Characteristics and Applications Question Answer (2026-27)
https://www.tiwariacademy.com/ncert-solutions/class-9/science/exploration-chapter-10/
See lessThe sound waves emitted by three sources A, B and C are represented in Fig. 10.31. If the frequency of A is maximum and C is minimum, identify the corresponding curves and mark A, B and C on them.
Since wave speed in a medium is constant, frequency is inversely proportional to wavelength. Therefore, source A with maximum frequency corresponds to the green curve having the shortest wavelength and most cycles. Source C with minimum frequency corresponds to the blue curve having the longest waveRead more
Since wave speed in a medium is constant, frequency is inversely proportional to wavelength. Therefore, source A with maximum frequency corresponds to the green curve having the shortest wavelength and most cycles. Source C with minimum frequency corresponds to the blue curve having the longest wavelength. Source B corresponds to the intermediate red curve.
For more NCERT Solutions of Class 9 Science Exploration Chapter 10 Sound Waves Characteristics and Applications Question Answer (2026-27)
https://www.tiwariacademy.com/ncert-solutions/class-9/science/exploration-chapter-10/
See lessIn a movie, while showing the explosion of a spacecraft in space, a flash of light is shown along with sound at the same time. What are the errors in this depiction?
(i) Sound propagation error: Outer space is a near vacuum lacking a material medium and since sound is a mechanical wave requiring matter to propagate, no explosion sound can travel or be heard. (ii) Simultaneous arrival error: Even if gas were present, light travels at nearly 300,000 km per second,Read more
(i) Sound propagation error: Outer space is a near vacuum lacking a material medium and since sound is a mechanical wave requiring matter to propagate, no explosion sound can travel or be heard. (ii) Simultaneous arrival error: Even if gas were present, light travels at nearly 300,000 km per second, meaning visual flash would always arrive long before any acoustic disturbance.
For more NCERT Solutions of Class 9 Science Exploration Chapter 10 Sound Waves Characteristics and Applications Question Answer (2026-27)
https://www.tiwariacademy.com/ncert-solutions/class-9/science/exploration-chapter-10/
See less