# Homework Help: Light Waves

1. May 15, 2006

### BTruesdell07

I know that light waves move in three dimensions, however I do not get in what way, for example: a sound wave looks sinusoidal. So my question is this: what does a 3-D light wave look like?

2. May 15, 2006

### Staff: Mentor

3. May 16, 2006

### BobG

Depends on the wavelength. If the wave has a wavelength of around 450 nanometers, the wave looks kind of blue. Around 650 nanonmeters, it looks kind of red. :rofl:

Light waves are still sinusoidal. They just propagate in a spherical pattern. That means you don't really have parallel light waves. Each 'parallel' light wave is really getting just a little bit further away from its companion, hence the inverse square law for the intensity of light.

4. May 16, 2006

### dimensionless

A pulse of light would look like a sphere whose diameter gradually increases over time. The sphere would be centered at the lightwave's source. If the light source is continuous, as it usually is, you would see a series of spheres just like the one I described above. The distance between each sphere is equal to the wavelength.