Question

Light waves move through space at a speed of ______ meters per second.

Short answer

Light waves move through space at a speed of approximately \(3 \times 10^8\) meters per second.

Step-by-step solution

Speed of Light

The speed of light in a vacuum is approximately \(3 \times 10^8\) meters per second.

Key concepts

Light Waves

Light waves are a type of electromagnetic wave. They are a form of energy that travels through space. This energy doesn't need a medium, meaning they can move through empty space as well as through some materials. Light waves have specific characteristics, like wavelength, frequency, and speed. Wavelength is the distance between two peaks of a wave, whereas frequency is how often these peaks pass a certain point in a given time.
When light waves enter a medium like glass or water, their speed changes, though their frequency stays the same. This slowing effect is why light bends when moving from one substance to another, a phenomenon known as refraction.

• Electromagnetic nature: light waves are part of the electromagnetic spectrum, which includes radio waves, microwaves, and X-rays.
• Interaction with matter: when interacting with different materials, light's speed changes resulting in phenomena like bending or scattering.

Vacuum

A vacuum is a space void of matter. It's the 'emptiness' between celestial bodies like stars and planets. Here, there are hardly any particles to interfere with the travel of light waves. This lack of interference allows light to travel at its maximum speed.
The concept of a vacuum is essential in physics because it represents an ideal condition. In a vacuum, light travels unimpeded, reaching its top speed of approximately \(3 \times 10^8\) meters per second.

• Ideal conditions: in a vacuum, there are no particles to scatter or absorb light.
• Importance in physics: studying how phenomena behave in a vacuum helps us understand their fundamental nature.

Meters per Second

The phrase "meters per second" is a unit of speed in the International System of Units (SI). It tells us how many meters an object, like a light wave, travels every second. In vacuum, light travels at a staggering \(3 \times 10^8\) meters per second.
This speed is incredibly fast, allowing light from the Sun to reach Earth in about 8 minutes. Scientists use this measurement when comparing the speed of anything moving at or close to the speed of light.

• SI unit of speed: meters per second is universally used in physics for measuring speed.
• Significance in astronomy: this unit helps astronomers measure vast cosmic distances.