The velocity of electromagnetic waves in a dielectric medium with relative permittivity of 4 will

This question was previously asked in

SDSC (ISRO) Technical Assistant (Electronics): Previous Paper 2018 (Held On: 8 April 2018)

Option 3 : 1.5 × 10^{8} m/s

CT 1: Network Theory 1

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10 Marks
10 Mins

__Concept:__

The velocity (V_{p}) of a plane electromagnetic wave is given as-

\({V_p} = \frac{1}{{\sqrt {μ \varepsilon } }}\)

Here, μ = μ_{o}μ_{r}

ε = ε_{o} ε_{r}

\({v_p} = \frac{1}{{\sqrt {{μ _o}{μ _r}{\varepsilon _o}{\varepsilon _r}} }}\)

\({v_p} = \frac{c}{{\sqrt {{μ _r}{\varepsilon _r}} }}\)-----(1)

\(c = \frac{1}{{\sqrt {{μ _o}{\varepsilon _o}} }} = 3 \times {10^8}\;m/sec\)

μ0 = permeability in free space 4π × 10^{-7} H/m

εo = permittivity in free space 8.854 × 10^{-12} C^{2}/Nm^{2}

__Calculation:__

Given:

μ_{r} = 4

From Equation (1):

\(v_p=\frac{3\times10^8}{\sqrt4}\)

v_{p} = 1.5 x 10^{8} m/sec