Two forces $P$ and $Q$, of magnitude $2F$ and $3F$, respectively, are at an angle $\theta $ with each other. If the force $Q$ is doubled, then their resultant also gets doubled. Then, the angle $\theta $ is ....... $^o$

  • [JEE MAIN 2019]
  • A

    $120$

  • B

    $60$

  • C

    $90$

  • D

    $30$

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