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JEE Main 2021 (1 Sep, Shift 2) · Speed of EM Waves in a Medium

Speed of EM Waves in a Medium question from JEE Main 2021 (1 Sep, Shift 2)

Q20JEE Main 2021 · 1 SEP · SHIFT 2Medium

Speed of EM Waves in a Medium

Electric field of plane electromagnetic wave propagating through a non-magnetic medium is given by

E = 20cos(2 $\times$ 1010 t $-$ 200x) V/m. The dielectric constant of the medium is equal to: (Take $\mu$ r = 1)

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Answer: (a)

$v = \omega/k = \dfrac{2 \times 10^{10}}{200} = 10^{8}$ m/s
$n = c/v = 3$
Non-magnetic: $K = n^2 = 9$
So the answer is (a) 9.

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