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NEET2013PhysicsCurrent ElectricityActual

A wire of resistance 4 is stretched to twice its original length. The resistance of stretched wire would be

Options

  1. A2
  2. B4
  3. C8
  4. D16

Correct answer

D. 16

Step-by-step solution

Let length and cross-section area of the wire be l and A respectively. ( ) Resistance ( R = l A ) where ( ) is the resistivity of the material Given: (R=4 ) For (l^ =2 l ) and (A^ = A 2 ), resistance of the wire be (R^ ) ( aligned & R^ = l^ A^ = 2 l A / 2 =4 1 A =4 R & R^ =4 4 =16 aligned )

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