Study Guide: Speed of Light
- What is light?
- What is the dual wave-particle nature of light?
- What is the dual magnetic-electric nature of light?
- What is the speed of light?
- Why is the speed of light?
- How does light travel?
- What is the electromagnetic spectrum?
| Term | Description |
|---|---|
| FPS | Frames per second |
| Particle | A unit of matter |
| Photon | An elementary particle of light |
| Speed of Light | 186,000 mi/s |
| Wave | An oscillation through space |
The Speed of Light
Electromagnetic energy waves travel at what we call the Speed of Light. Why light travels at exactly this speed is not known. This is one of the deepest mysteries of physics.
$$ \textit{Speed of Light } = 299,792,458 \textit{ meters per second} $$
This constant is often shown in equations with the variable ‘c’, as in Einstein’s famous equation, Energy is equal to matter times the speed of light squared.
$$ e = mc^2$$
In a vacuum—such as deep space—the velocity of an electromagnetic energy wave ‘c’, is directly related to the wave’s frequency and wavelength by the following equation.
$$ c = \dfrac{\textit{Frequency (Hz)}}{\textit{Wavelength (in meters)}} $$
Stop to think about this equation for a moment. If ‘c’ is a constant, then the frequency and wavelength can only change in direct relation to each other. The amazing thing is that this seems to be true anywhere in the universe-without exception. Thus, this simple equation describes a universal truth about reality. (Whatever that means!)