Question

duction to waves
in an experiment, a ringing bell is placed in a vacuum jar that does not have any air in it. what best describes why the bell is seen vibrating but not heard?
light is a longitudinal wave that is able to pass through the vacuum jar, but sound is a transverse wave that has to move perpendicular to air.
light waves travel faster than sound waves, so they are able to travel through the vacuum jar, but sound waves do not have enough energy to vibrate glass.
light does not need a medium to travel through, but since sound waves must have a medium to vibrate, sound is not created where no air is present.
light waves have high frequencies and are able to pass through the vacuum jar, but the frequencies of...

Explanation:

To solve this, we analyze the properties of light and sound waves:

• Sound waves are mechanical waves, meaning they require a medium (like air, liquid, or solid) to travel. In a vacuum (no air), there's no medium for sound to propagate, so the bell's sound isn't heard.
• Light waves are electromagnetic waves. Electromagnetic waves do not need a medium to travel—they can move through a vacuum (like how sunlight reaches Earth through space). So we can see the bell vibrating (via light waves traveling through the vacuum jar) but can't hear it (since sound waves can't travel in a vacuum).

Now let's analyze the options:

• First option: Incorrect. Light is a transverse wave, and sound is a longitudinal wave (not the other way around as stated here). Also, the description of sound's movement is wrong.
• Second option: Incorrect. The issue isn't about light being faster or sound not vibrating glass. The core is the medium requirement for sound.
• Third option (the one about light not needing a medium, sound needing a medium): Correct. This matches the properties of electromagnetic (light) and mechanical (sound) waves.
• The partially visible option: Doesn't make sense in context (mentions light frequencies but that's not relevant to why sound isn't heard in a vacuum).

Answer:

The option stating "Light does not need a medium to travel through, but since sound waves must have a medium to vibrate, sound is not created where no air is present" (the third option in the provided image).