Key Stage 3 (KS3) Physics Practice Test

The statement that light can travel through a vacuum, but sound cannot, accurately describes a fundamental difference between the two types of waves. Light is an electromagnetic wave, which means it does not require a medium to propagate. This allows it to travel through the vacuum of space, such as the vast emptiness between celestial bodies.

On the other hand, sound is a mechanical wave, which means it requires a medium—such as air, water, or solid materials—to travel. Without a medium, sound cannot propagate and therefore cannot be heard in a vacuum. This distinction is crucial in understanding the different behaviors of sound and light waves in various environments.

The other statements do not hold true: sound does not travel faster than light; in fact, light travels much faster. Light also does not require a medium to travel, which is the opposite of sound. Hence, the correct understanding of the nature of sound and light demonstrates why this statement is accurate.