JEE Main · 2021 · 18 Mar 2021 · Shift 1 · Units & Measurement

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In the experiment of Ohm's law, a potential difference of 5.0 V is applied across the end of a conductor of length 10.0 cm and diameter of 5.00 mm. The measured current in the conductor is 2.00 A. The maximum permissible percentage error in the resistivity of the conductor is:
  1. (A)3.9✓ Correct
  2. (B)8.4
  3. (C)3.0
  4. (D)7.5

Answer: (A)

Solution

Resistivity follows from , so the maximum fractional error is

Each reading carries an uncertainty of one unit in its last recorded digit, so V, A, mm and cm. Then

The maximum permissible percentage error in the resistivity is .

JEE Main · 2021 · 18 Mar 2021 · Shift 1 · Single correct option

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