# Homework Help: As you move away from a lightsource

1. Nov 5, 2007

### grantP

As you move away from a lightsource....

1. The problem statement, all variables and given/known data
(from title)
.........the wavelength of the light _______? (increase, stays the same, decrease, decrease in amplitude?)

2. Relevant equations

3. The attempt at a solution

2. Nov 5, 2007

### grantP

my guess would be the wavelength would stay the same, but im not certain at all, anyone know?

3. Nov 5, 2007

### Antineutron

explain why you believe it would stay the same.

4. Nov 6, 2007

### grantP

well because wavelength is the distance between two successive points on waves right? well as you move away, the length dosent change, just the amount or possibly the frequency?

5. Nov 6, 2007

### slakedlime

This is just a theory. Technically neither the frequency or wavelength change. But for the observer, if you account for the Doppler effect, light sources/stars moving away from the earth appear to have a 'red shift' while those moving towards earth have a 'blue shift'. Red light has a longer wavelength than blue light. Frequency appears to decrease, but speed of light remains the same.