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JEE Main202623 January 2026Morning ShiftPhysicsMathematics in PhysicsActual

Four persons measure the length of a rod as 20.00 ~cm , 19.75 ~cm , 17.01 ~cm and 18.25 cm. The relative error in the measurement of average length of the rod is :

Options

  1. A0.08
  2. B0.06
  3. C0.18
  4. D0.24

Correct answer

B. 0.06

Step-by-step solution

Mean = 20.00+19.75+17.01+18.25 4 = 75.01 4 = 18.7525 cm. Absolute errors: |20.00-18.7525|=1.2475 , |19.75-18.7525|=0.9975 , |17.01-18.7525|=1.7425 , |18.25-18.7525|=0.5025 . Mean absolute error = 1.2475+0.9975+1.7425+0.5025 4 = 4.49 4 = 1.1225 . Relative error = 1.1225 18.7525 0.06 .

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