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KVPY2011PhysicsCurrent Electricity

A cylindrical copper rod has length L and resistance R . If it is melted and formed into another rod of length 2 ~L , the resistance will be

Options

  1. AR
  2. B2 R
  3. C4 R
  4. D8 R .

Correct answer

C. 4 R

Step-by-step solution

Applying volume conservation array l A L = A ^ 2 ~L ~A ^ = A 2 R = L A R ^ = 2 ~L ~A ^ = 4 ~L ~A R ^ =4 R array

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