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NEET2020PhysicsAlternating CurrentActual

A light bulb and an inductor coil are connected to an ac source through a key as shown in the figure below. The key is closed and after sometime an iron rod is inserted into the interior of the inductor. The glow of the light bulb

Options

  1. Adecreases
  2. Bremains unchanged
  3. Cwill fluctuate
  4. Dincreases

Correct answer

A. decreases

Step-by-step solution

We know that the formula of impedance for L - R circuit, Z = R 2 + X L 2 , here, R = resistance and X L = ω L , where, L is the inductance when we insert the iron rod in inductor then the value of L increased and then the value of impedance also increased, and due to constant voltage current will be decreased across the bulb and the glow of the bulb will decrease.

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