Chapter 25, Problem 85GP

Predict/Calculate At a particular instant of time, a light beam traveling in the positive z direction has an electric field given by $\stackrel{\to }{\text{E}}=\left(6.22N/C\right)\stackrel{⌢}{\text{x}}\text{+}\left(2.87N/C\right)\stackrel{⌢}{\text{y}}$. The magnetic field in the beam has a magnitude of 2.28 × 10⁻⁸ T at the same time (a) Does the magnetic field at this time have a z component that is positive negative, or zero? Explain (b) Write $\stackrel{\to }{\text{B}}$ in terms of unit vectors.