Parameters and the nature of electromagnetic waves

[greg_rack]

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:
f_P/f_Q=10^-8xV_P/V_Q
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.

 

[TSny]

Does the speed of light in vacuum depend on the wavelength?

 

[greg_rack]

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]

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.

 

[greg_rack]

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]

If v=c=f•lambda, but c is fixed... is this formula still “working”? Should I use that?

Yes, definitely.