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Alternating Current question

2001 · Q133
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Alternating Current question

2001 · Q133

NEETPhysicsAlternating CurrentMCQ+4 / −1
A capacitor of capacity C has reactance X. If capacitance and frequency become double then reactance will be
  1. A
    4X
  2. B
    X/2
  3. C
    X/4
  4. D
    2X
View written solutionFree

Correct answer: C

Reactance X = 1ωC=12πfC{1 \over {\omega C}} = {1 \over {2\pi fC}}ωC1​=2πfC1​

∴\therefore∴ X ∝\propto∝ 1fC{1 \over {fC}}fC1​

∴\therefore∴ X1X=fCf1C1{{{X_1}} \over X} = {{fC} \over {{f_1}{C_1}}}XX1​​=f1​C1​fC​ = fC2f×2C{{fC} \over {2f \times 2C}}2f×2CfC​ = 14{1 \over 4}41​

⇒\Rightarrow⇒ X1 = X4{X \over 4}4X​

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