Question

Show the speed of light in air equals 3x10⁸ m/s if the wave travelled with a frequency of 9.7x10¹² Hz with a wavelength 3.09x10^-5 m.

Answer 1

$$c=f\lambda=9.7\cdot10^{12}\ Hz\cdot3.09\cdot10^{-5}\ m=3\cdot10^8\ \dfrac{m}{s}.$$