The amplitude of a sound wave is reduced from 2 mm to 1 mm. The intensity of the sound will:

become one fourth of the initial

Reason —

Given,

• Initial amplitude = 2 mm
• Final amplitude = 1 mm

As,

Intensity of a sound wave ∝ (Amplitude of vibrations)²

Then,

$\frac{\text {Final intensity}}{\text {Initial intensity}} = \left({\frac{\text {Final amplitude}}{\text {Initial amplitude}}}\right)^2 = \left(\frac{1}{2}\right)^2 = \frac {1}{4}$

So,

Final intensity = $\frac {1}{4}$ x Initial intensity