find the wavelength of electromagnetic wave of frequency 4x10⁹ Hz in free space. give its two applications.

$$\begin{gathered} We know , \\ c= \nu \times \lambda \\ where c is velocity of light in free space \\ \nu is frequency \\ \lambda is wavelength \\ 3\times {10}^8 = 4 \times {10}^{9 }\times \lambda \\ so , \\ \lambda =0.075 m \end{gathered}$$


Applications-
Electromagnetic waves have wide range of  wavelength.
1.Radiowaves which is part of EM waves are used in TV and FM radio.
2. Microwaves used in cooking.