12th Class Physics Alternating Current / प्रत्यावर्ती धारा Question Bank MCQs - Alternating Current

  • question_answer
    If the rms current in a 50 Hz AC circuit is 5 A, the value of the current 1/300 s after its value becomes zero is

    A) \[5\sqrt{2}\operatorname{A}\]

    B) \[5\sqrt{\frac{3}{2}}\operatorname{A}\]

    C) \[\frac{5}{6}\]A

    D) \[\frac{5}{\sqrt{2}}\operatorname{A}\]

    Correct Answer: B

    Solution :

    Option [b] is correct
    Explanation: Here, \[{{I}_{\operatorname{rms}}}\]=5 A, n 50 Hz and \[t\frac{1}{300}s\]
    = Peak value =\[\sqrt{2}{{\operatorname{I}}_{rms}}=\sqrt{2}\times 5=5\sqrt{2}\operatorname{A}\]
    Now, I = \[{{I}_{0}}\ \sin \ \omega t=5\sqrt{2}\ \sin \ 2\pi vt\]
    \[=5\sqrt{2}\ \sin \ 2\pi \times 50\times \frac{1}{300}=5\sqrt{\frac{3}{2}}A\]


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