Using Equation given below the magnitude of \(B\) is
\(B=\frac E c\)
\(=\frac{3.3}{3\times 10^8}=2.1\times 10^{-8}\;T\)
To find the direction. we note that \(E\) is along \(Y\text{-direction}\) and the wave propagates along \(X \text{-axis}.\) Therefore, \(B\) should be in a direction perpendicular to both \(X-Y\text{ axis.}\) Using vector algebra. \(E\times B\) should be along \(X\text{-direction}.\) Since, \(\text j\times +\text k=1,B\) is along the \(Z\text{-direction}.\) Thus. \(b=2.1\times 10^{-8}\;kT.\)