Ultrasound's everyday applications

Steps:

• Ultrasound refers to sound waves above 20 kHz, beyond human hearing.
• Common uses include medical imaging, industrial cleaning, and sonar.
• Evaluate options: identify which matches a known ultrasound application.
• Select A, as ultrasonic cleaners are standard for delicate items like jewellery.

Why A is correct:

• Ultrasound generates high-frequency vibrations that produce cavitation bubbles in liquid, dislodging dirt from surfaces without damage, as per the principle of acoustic cavitation.

Why the others are wrong:

• B: Optical fibres transmit light signals for data, unrelated to sound waves.
• C: Fluorescent tubes emit light through electron excitation in gas, not ultrasound.
• D: Sunbeds use ultraviolet radiation for skin tanning, involving electromagnetic waves, not sound.

Final answer: A