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Alternating Current question

2021 · 17 Mar · Shift 2 · Q45
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Alternating Current question

2021 · 17 Mar · Shift 2 · Q45

JEE MainPhysicsAlternating CurrentMCQ+4 / −1
Match List - I with List - II

List - I List - II
(a) Phase difference between current and voltage in a purely resistive AC circuit (i) π2{\pi \over 2}2π​; current leads voltage
(b) Phase difference between current and voltage in a pure inductive AC circuit (ii) zero
(c) Phase difference between current and voltage in a pure capacitive AC circuit (iii) π2{\pi \over 2}2π​; current lags voltage
(d) Phase difference between current and voltage in an LCR series circuit (iv) tan⁡−1(XC−XLR){\tan ^{ - 1}}\left( {{{{X_C} - {X_L}} \over R}} \right)tan−1(RXC​−XL​​)


Choose the most appropriate answer from the options given below :
  1. A
    (a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)
  2. B
    (a)-(i), (b)-(iii), (c)-(iv), (d)-(ii)
  3. C
    (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
  4. D
    (a)-(ii), (b)-(iv), (c)-(iii), (d)-(i)
View written solutionFree

Correct answer: A

  1. Purely resistive AC circuit
    In a resistor, current and voltage are in phase. Hence phase difference is ϕ=0\phi = 0ϕ=0 So, (a)→(ii)(a) \to (ii)(a)→(ii)

  2. Pure inductive AC circuit
    In an inductor, current lags voltage by π2\frac{\pi}{2}2π​.
    So phase difference is π2; current lags voltage\frac{\pi}{2}\text{; current lags voltage}2π​; current lags voltage Thus, (b)→(iii)(b) \to (iii)(b)→(iii)

  3. Pure capacitive AC circuit
    In a capacitor, current leads voltage by π2\frac{\pi}{2}2π​.
    So, (c)→(i)(c) \to (i)(c)→(i)

  4. LCR series circuit
    For a series LCRLCRLCR circuit, the phase angle is given by tan⁡ϕ=XL−XCR\tan \phi = \frac{X_L - X_C}{R}tanϕ=RXL​−XC​​ If written for current with respect to voltage, equivalently the listed form is tan⁡−1(XC−XLR)\tan^{-1}\left(\frac{X_C-X_L}{R}\right)tan−1(RXC​−XL​​) which matches the given option (iv). Thus, (d)→(iv)(d) \to (iv)(d)→(iv)

  5. Final matching

(a)−(ii),(b)−(iii),(c)−(i),(d)−(iv)(a)-(ii),\quad (b)-(iii),\quad (c)-(i),\quad (d)-(iv)(a)−(ii),(b)−(iii),(c)−(i),(d)−(iv)

This corresponds to Option A.

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