Question

Electromagnetic waves travel in a medium which has relative permeability 1.3 and relative permittivity 2.14. Then the speed of the electromagnetic wave in the medium will be

• A. $ 13.6\,\times {{10}^{6}}\,m/s $
• B. $ 1.8\times {{10}^{2}}\,m/s $
• C. $ 3.6\,\times {{10}^{8}}\,m/s $
• D. $ 1.8\times {{10}^{8}}\,m/s $

Answer 1

Answer: (D)

The speed of electromagnetic wave in medium is $ \upsilon =\frac{c}{\sqrt{{{\mu }_{r}}{{\varepsilon }_{r}}}}=\frac{3\times {{10}^{8}}}{\sqrt{1.3}\times 2.14}=\frac{3\times {{10}^{8}}}{1.67} $ $ =1.8\times {{10}^{8}}\,m/s $