Relating B and E in an electromagnetic wave

[Revvi]

Homework Statement

I need to determine B(rms) in terms of E(max) given a standard E-M wave.

Homework Equations

E = cB

The Attempt at a Solution

I assumed that B(max) is sqrt(2) x B(rms) and then just plugged in for B(max) in the equation above. Am I right in assuming the rms value involves a square root? (I get confused if it's 2 or sqrt(2))

 

[kuruman]

You are right. The max value is greater than the rms value by a factor of sqrt(2).