Question

Suppose you were to play a trumpet after breathing helium, in which the speed of sound is much greater than in air. Would the pitch of the instrument be higher or lower than normal, or would it be unaffected by being played with helium inside the tube rather than air?

Answer 1

The pitch will be higher.

Step-by-step explanation:

The pitch of an instrument is a factor of the frequency of the sound of it. At an open tube, the frequency of the sound depends on the harmonic, which are stages of the waves of the sound inside the instrument:

f = n*v/2L

Where f is the frequency, v is the velocity, n is the number of the harmonic, and L is the wavelength. So, the frequency is directly proportional to the velocity, and f the speed (velocity) is higher, the frequency will be higher, and the pitch will be higher too.