The wave function (in S.I. units) for an electromagnetic wave is given as: $\Psi(x, t)=10^3 \sin \pi\left(3 \times 10^6 x-9-10^{14} t\right)$ The speed of the wave as:

9 × 1014 m/s 3 × 108 m/s 3 × 1016 m/s 3 × 107 m/s

3 × 108 m/s

c = $\frac{\omega}{k}=\frac{9 \times 10^{14}}{3 \times 10^6}$ = 3 × 108 m/s