(a) Discuss two important practical applications of ultrasound: (i) Cleaning hard-to-reach intricate parts of machines, and (ii) Medical treatment of kidney stones. (b) Differentiate clearly between Loudness and Intensity of sound. State the factor on which loudness primarily depends. (c) A sound source generates 1200 compressions and 1200 rarefactions in $3 ext{ seconds}$. The distance between a compression and its immediate consecutive rarefaction is $0.25 ext{ m}$. Calculate: Frequency of the wave Wavelength of the wave Speed of the sound wave

Question

(a) Discuss two important practical applications of ultrasound: (i) Cleaning hard-to-reach intricate parts of machines, and (ii) Medical treatment of kidney stones. (b) Differentiate clearly between Loudness and Intensity of sound. State the factor on which loudness primarily depends. (c) A sound source generates 1200 compressions and 1200 rarefactions in $3	ext{ seconds}$. The distance between a compression and its immediate consecutive rarefaction is $0.25	ext{ m}$. Calculate: Frequency of the wave Wavelength of the wave Speed of the sound wave

Accepted Answer

(a) Applications of Ultrasound Cleaning Intricate Parts: Ultrasonic waves are used to clean objects located in hard-to-reach places, such as spiral tubes, odd-shaped electronic components, or delicate machinery. The object to be cleaned is placed in a cleaning solution, and ultrasonic waves (frequency $> 20	ext{ kHz}$) are passed through it. High-frequency vibrations shake the solution violently, causing dust, grease, and dirt particles to detach and drop off, leaving the parts completely clean. Treatment of Kidney Stones (Lithotripsy): High-intensity ultrasonic waves are focused directly onto small stones (kidney stones) formed in the kidneys. The high-frequency mechanical vibrations break the stones into extremely fine sand-like particles. These tiny particles are later flushed out naturally from the body along with urine without requiring surgical intervention. --- (b) Distinction Between Loudness and Intensity of Sound | Feature | Loudness | Intensity | | :--- | :--- | :--- | | Definition | Subjective perception of sound energy by the human ear. | Objective measure of sound energy passing per unit area per second. | | Measurement | Cannot be measured directly with an instrument; felt by ears. | Physical quantity measured in Watt per square meter ($	ext{W/m}^2$). | | Dependence | Depends on both sound energy and sensitivity of the listener's ear. | Independent of ear sensitivity. | Factor affecting loudness: Loudness depends primarily on the amplitude of the vibrating body. Larger amplitude produces a louder sound.

Feature	Loudness	Intensity
Definition	Subjective perception of sound energy by the human ear.	Objective measure of sound energy passing per unit area per second.
Measurement	Cannot be measured directly with an instrument; felt by ears.	Physical quantity measured in Watt per square meter ($\text{W/m}^2$).
Dependence	Depends on both sound energy and sensitivity of the listener's ear.	Independent of ear sensitivity.