# Light wave

1. Feb 9, 2006

### Wishbone

The problem gives the angular frequency of a light wave (w) is represented by

e^iw(t-nx/c)

it says that sometimes n is replaced by the complex quantity n-ik.

The question asks what is the effect of k on the wave. Also, it asks, what is its physical signifigance?

I tried substituting in for n-ik for n, and then multiplying in the iw.

I got: e^ (iwt-iwnx +kx)/c

So I see that the k term is the only real term in the exponent, however I am not sure how that effects the wave, or what its physical signifigance is.

2. Feb 9, 2006

### quasar987

I don't think that is correct. Doing the calculations, I get, after putting into an illuminating form:

$$e^{-kx/c}e^{i(wt-nx/c)}$$

What kind of a wave is that? (i.e. what is the effect of k on the wave?)

3. Feb 9, 2006

### Wishbone

thats a dampened wave, isn't it?

4. Feb 9, 2006

### Wishbone

and the larger the K, the quicker the wave dies?

5. Feb 10, 2006

### quasar987

yep.

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6. Feb 10, 2006

### Wishbone

sweet, thx dude.