Characteristics of Sound - UNSOLVED PRACTICE SET

Q7. Define pitch of sound. How is pitch related to frequency? Give one example each of a high-pitched and low-pitched sound from Indian daily life.

Q8. What is loudness? On what physical property of the wave does it depend? Give one example showing that the same sound can be loud or soft depending on distance.

Q9. What is the quality or timbre of sound? Why does a sitar and a violin sound different even when they play the exact same note at the same volume?

Q10. Define the amplitude of a sound wave. How does amplitude affect the energy carried by a sound wave? Relate this to why loud sounds can sometimes cause physical damage

Q11. A school bell rings at 80 dB and a whisper is about 30 dB. The pain threshold for sound is around 120 dB. Explain what the decibel scale represents and why noise pollution above 85 dB is harmful for long exposures.

Q12. Explain the difference between a musical note and noise. Why does a harmonium playing a sur (note) sound pleasant while a vehicle horn blaring in traffic feels unpleasant?

Q13. Explain the three main characteristics of sound — pitch, loudness, and quality — in detail. For each characteristic,
(a) define it clearly,
(b) state the physical property of the wave it depends on,
(c) give a real-life Indian musical or everyday example, and
(d) explain what happens to that characteristic if the relevant property is doubled.

Q14. A music teacher in a Carnatic music class plays the same note (Sa) on a veena, a flute, and a mridangam.
(a) Would the pitch be the same for all three? Explain.
(b) Would the loudness be the same? What determines it?
(c) Why can a trained musician immediately tell which instrument is being played even with eyes closed?
(d) What physical wave characteristic creates this ability to distinguish instruments?
(e) If the veena is plucked more forcefully, how does this affect the wave's amplitude, frequency, and the sound heard?

Q15. Noise pollution is a serious problem in Indian cities.
(a) Define noise and explain how it differs physically from musical sound (in terms of wave regularity).
(b) List four sources of noise pollution in an Indian city.
(c) What are the health effects of prolonged exposure to sounds above 85 dB?
(d) What is the safe recommended level of noise for residential areas in India?
(e) Suggest four practical measures to reduce noise pollution in a school that is situated near a busy highway.

Q16. A tabla produces a note of frequency 200 Hz and a flute produces a note of frequency 800 Hz. Both are playing at the same amplitude.
(a) Which instrument produces the higher-pitched sound?
(b) Using speed of sound = 340 m/s, calculate the wavelength of each note.
(c) Which note has the longer wavelength?
(d) If the tabla player strikes harder (increasing amplitude) but at the same frequency, which characteristic of sound changes and which stays the same?

Q17. A loudspeaker produces sound at 70 dB at a distance of 1 m. In a concert hall, the sound engineer wants the sound at 25 m to still be audible (above 40 dB).
(a) The intensity of sound decreases with distance. Describe qualitatively what happens to loudness as you move farther from the speaker.
(b) Why do concert halls use multiple speakers rather than one very loud speaker?
(c) If the amplitude of vibration of the speaker cone is doubled, by what factor does the intensity of the sound increase? (Intensity ∝ amplitude²)

Q18. A student notices that her teacher's voice sounds different over the phone compared to in person, even though she can recognise it is the same person.
(a) Which characteristic of sound helps her recognise her teacher's voice?
(b) Which characteristic is affected by the phone's speaker quality?
(c) The phone amplifies the signal — which characteristic increases as a result?
 (d) If the teacher speaks at 256 Hz and the phone slightly alters it to 260 Hz, would the student notice a pitch change? What does this tell you about human perception of small frequency changes?