An antenna is placed in a dielectric medium of dielectric constant $6.25$. If the maximum size of that antenna is $5.0\, mm$. it can radiate a signal of minimum frequency of $GHz .$

(Given $\mu_{ r }=1$ for dielectric medium)

  • [JEE MAIN 2022]
  • A

    $60$

  • B

    $6$

  • C

    $9$

  • D

    $3$

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