Answer:
Sound waves travel faster in a low-density gas
Explanation:
First of all, let's remind that sound waves are pressure waves: they consist of oscillations of the particles in a medium, which oscillate back and forth along the direction of motion of the wave (longitudinal wave).
The speed of sound in an ideal gas is given by the equation
where
is the adiabatic index of the gas
p is the gas pressure
is the gas density
From the equation, we see that the speed of sound is inversely proportional to the square root of the density: therefore, the lower the density, the faster the sound waves.
So, sound waves will travel faster in a low-density gas.