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NEET2013PhysicsAlternating CurrentActual

A coil of self-inductance L is connected in series with a bulb B and an A C source. Brightness of the bulb decreases when

Options

  1. Afrequency of the AC source is decreased
  2. Bnumber of turns in the coil is reduced
  3. Ca capacitance of reactance X_C=X_L is included in the same circuit
  4. Dan iron rod is inserted in the coil

Correct answer

D. an iron rod is inserted in the coil

Step-by-step solution

As Z= R^2+X_L^2 = R^2+(2 f V L)^2 As /= V Z , P=/^2 R i.e., V , L Z , / and P

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