# Parameters and the nature of electromagnetic waves

## Homework Statement:

Two electromagnetic waves P and Q travel in a vacuum and the ratio of their wavelengths is 1x10^8
Which row in the table shows the ratio of their speeds, the ratio of their frequencies, and
identifies the possible natures of P and Q?
I'll attach the table below

## Relevant Equations:

v=f lambda

By rearranging over and over ratio formulas involving frequency, speed and wavelength, I came up with the equation:
fP/fQ=10^-8xVP/VQ
This led me to take into account only rows A, B, E, and F... but I can't really understand which one of these is the right one.

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TSny
Homework Helper
Gold Member
Does the speed of light in vacuum depend on the wavelength?

Does the speed of light in vacuum depend on the wavelength?
Well, no, but isn’t “c” fixed even if not in a vacuum?

TSny
Homework Helper
Gold Member
For this problem the light is traveling in a vacuum. So the speed is c for all frequencies.

When light travels in a material medium, the speed generally varies with frequency.

For this problem the light is traveling in a vacuum. So the speed is c for all frequencies.

When light travels in a material medium, the speed generally varies with frequency.
Oh, I didn’t know all electromagnetic waves were traveling at c in a vacuum!
And now, how could I find both frequencies in order to establish their natures?
If v=c=f•lambda, but c is fixed... is this formula still “working”? Should I use that?

TSny
Homework Helper
Gold Member
If v=c=f•lambda, but c is fixed... is this formula still “working”? Should I use that?
Yes, definitely.