Basic physics question??? 1. The problem statement, all variables and given/known data 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?" 2. Relevant equations 3. 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.