The electric field of an electromagnetic wave travelling through vacuum is given by the equation E0 = E sin(kx − ωt) .The quantity that is independent of wavelength is:
Answer & explanation
Correct answer: option 2
Here, $k=\frac{2 \pi}{\lambda}, \omega=2 \pi v$
∴ $\frac{k}{\omega}=\frac{2 \pi / \lambda}{2 \pi v}=\frac{1}{v \lambda}=\frac{1}{c}$ $(∵ c=v \lambda)$
Where c is the speed of electromagnetic wave in vacuum. It is a constant whose value is 3 × 108 ms-1.