If the musician then presses down on string and plucks it sound produces has a shorter wavelength How does pitch of change?

The pitch of a sound is determined by its frequency, which is the number of waves that pass a given point in one second. The higher the frequency, the higher the pitch.

When a musician presses down on a string and plucks it, the string vibrates at a higher frequency. This is because the string is shorter, so it has less mass to vibrate. The less mass an object has, the faster it can vibrate.

The higher frequency of vibration produces a sound with a shorter wavelength. This is because the wavelength of a sound wave is inversely proportional to its frequency. The higher the frequency, the shorter the wavelength.

So, when a musician presses down on a string and plucks it, the sound produced has a shorter wavelength and a higher pitch.