- Statement I: Sound waves are mechanical waves. They require a medium (solid, liquid, or gas) for propagation because they travel through the vibration of particles in the medium. Vacuum is devoid of such particles, hence sound cannot travel through vacuum. This statement is false. - Statement II: Light waves are electromagnetic waves. Electromagnetic waves do not require a material medium for propagation; they can travel through vacuum. This is why light from the Sun reaches the Earth through the vacuum of space. This statement is true.