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CUET · PHYSICS · PYQ PAPER 2023

What is the relative permittivity of a medium of relative permeability \( \mu_r = 1.0 \) in which an electromagnetic wave travels at a speed of \( v = 2 \times 10^8 \, \text{m s}^{-1} \)?

  1. A \( 1.5 \)
  2. B \( 0.44 \)
  3. C \( 2.25\)
  4. D \( 0.67\)
Verified Solution

Answer & Solution

Correct Answer

(C) \( 2.25\)

Step-by-step Solution

Detailed explanation

\( v = \frac{c}{\sqrt{\mu_r \varepsilon_r}} \) \( \varepsilon_r = \frac{1}{\mu_r} \left(\frac{c}{v}\right)^2 \) \( \varepsilon_r = \frac{1}{1.0} \left(\frac{3 \times 10^8}{2 \times 10^8}\right)^2 \) \( \varepsilon_r = (1.5)^2 = 2.25 \)