Calculating the Speed of an Electromagnetic Wave: Basic Physics Question

[SMA_01]

Basic physics question?

Homework Statement

My younger sister has a problem stated:

"An electromagnetic wave is found to have a frequency of 7.8x10^-10 Hz. What is the speed of the wave?"

Homework Equations

The Attempt at a Solution

It's been a while since I have done this, and I'm a little confused. I know that you typically use the formula: C=λv (C= speed of light, λ= wavelength, v=frequency). I'm not sure, but I was thinking maybe it's a trick question, because I thought electromagnetic waves all travel at the speed of light (~3x10⁸ m/s). Am I correct in assuming this?

Any help is appreciated.

Thanks.

 

[BruceW]

Yes, I think you are right, it is a trick question, since the speed of light in vacuum is always ~3x10⁸m/s