# Determine the velocity of a reference frame S

1. Jan 7, 2012

### Hydeyuki

Can someone give me a clue/hint to finish this question?

"In a reference frame S, the electric and magnetic fields of an electromagnetic wave E
and B are perpendicular to each other. Determine the velocity of a reference frame S'
in which (a) E' = 0 and (b) B' = 0"

2. Jan 8, 2012

### vela

Staff Emeritus
How do the electric and magnetic fields transform under a Lorentz boost?

3. Jan 8, 2012

### Markus Hanke

Yes, as vela said above - write down the Lorentz transformation rules for both E and B. You will see immediately what needs to happen to get E'=0 and B'=0...