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Let us consider a copper wire having radius r and length l . Let its resistance be R . If the radius of another copper wire is 2 r and the length is l / 2 then the resistance of this, wire will be

Options

  1. AR
  2. B2 R
  3. CR / 4
  4. DR / 8

Correct answer

D. R / 8

Step-by-step solution

Resistance R = l ~A aligned & R ₁= l ~A = R & R ₂= ( l 2 ) (2 r )^2 = l 8 ~A = R 8 aligned =

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