Quiz 1.4

The dispersion relation Eq. (1.17) for electromagnetic waves in vacuum can be rewritten

$$k\lambda=2\pi,\quad\omega T=2\pi\nu T=2\pi \qquad\Rightarrow\qquad\lambda\nu=c$$

Long wavelength means low frequency and short wavelength means high frequency.

$$\nu=\unit[100]{MHz}\Leftrightarrow\lambda=\unit[3]{m},\quad \nu=\... ...mbda=\unit[30]{cm},\quad \nu=\unit[10]{GHz}\Leftrightarrow\lambda=\unit[3]{cm}$$

A metal grid with $\Delta x,\Delta y<1$ protects from microwaves.