An electromagnetic wave of frequency 3 GHz enters a dielectric medium of relative electric permittivity 2.25 from vacuum. The wavelength of this wave in that medium will be _________ $\times$ 10^$-$2 cm.

Given, frequency of wave, f = 3 GHz = 3 $\times$ 10⁹ Hz<br/><br/>Relative permittivity, $\varepsilon$_r = 2.25<br/><br/>Since, f = C/$\lambda$<br/><br/>$$ \Rightarrow \lambda = {c \over f} = {{3 \times {{10}^8}} \over {3 \times {{10}^9}}} = 0.1$$ m<br/><br/>$\because$ $\lambda$_m (wavelength of wave in a medium) = $\lambda$/$\mu$ and we know that, $\mu = \sqrt {{\mu _r}{\varepsilon _r}}$<br/><br/>As, dielectric is non-magnetic, $\mu$_r = 1<br/><br/>$\Rightarrow \mu = \sqrt {2.25} = 1.5$<br/><br/>$\Rightarrow {\lambda _m} = {{0.1} \over {1.5}} = {1 \over {15}} = 0.0667$ m<br/><br/>= 6.67 cm = 667 $\times$ 10^$-$2 cm