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BITSAT2015PhysicsCurrent ElectricityActual

The resistance of a wire is R . It is bent at the middle by 180^ and both the ends are twisted together to make a shorter wire. The resistance of the new wire is

Options

  1. A2 R
  2. BR / 2
  3. CR / 4
  4. DR / 8

Correct answer

C. R / 4

Step-by-step solution

Resistance of wire (R)= l A If wire is bent in the middle then l^ = l 2 , A^ =2 A New resistance, R ^ = l^ A ^ = l 2 2 A = l 4 A = R 4

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