Loudness of sound is measured in

Question

Loudness of sound is measured in

1. A. decibel (dB) (Correct answer)
2. B. hertz (Hz)
3. C. metre (m)
4. D. metre/second (m/s)

Correct Answer

Option A — decibel (dB)

Detailed Solution & Explanation

The correct answer is decibel (dB).

Key Points

• Loudness, which depends on the amplitude of a sound wave, is measured in decibels (dB).
• Hertz (Hz) measures frequency, which determines pitch rather than loudness — a distinction the question is testing.
• Metre and metre/second measure wavelength and speed.

Additional Information

• The decibel scale is logarithmic: every increase of 10 dB represents a tenfold rise in intensity, so 60 dB is ten times as intense as 50 dB.
• Reference points: a whisper about 30 dB, normal conversation 60 dB, heavy traffic 85 dB, and above 120 dB sound becomes painful. Prolonged exposure beyond 85 dB risks hearing damage.
• Humans hear roughly 20 Hz to 20,000 Hz; below that is infrasound, above it ultrasound.