When a sound wave goes from one medium to another, the quantity that remains unchanged is

CONCEPT:

Properties of Sound Waves

Sound waves are mechanical waves that require a medium to travel through. They can propagate through solids, liquids, and gases.

When a sound wave travels from one medium to another, several properties of the wave can change, such as its speed, wavelength, and amplitude.

The frequency of a sound wave, however, remains unchanged when it moves from one medium to another.

EXPLANATION:

Let's examine the given options:

Option 1: Frequency

The frequency of a sound wave is determined by the source of the sound and does not change when the wave moves from one medium to another.

Option 2: Amplitude

The amplitude of a sound wave can change as it moves between different media due to the varying densities and elastic properties of the media.

Option 3: Wavelength

The wavelength of a sound wave changes when it enters a different medium because the speed of sound is different in different media.

Option 4: Speed

The speed of a sound wave varies depending on the medium through which it is traveling. For example, sound travels faster in solids than in liquids and gases.

Therefore, the correct answer is option 1: Frequency.