In the experiment of Ohm's law, a potential difference of 5 . 0   V is applied across the end of a…

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. 3.9
  2. 8.4
  3. 7.5
  4. 3.0

Solution

R=ρℓA=VI
ρ=AVIℓ=πd2 V4Iℓ  A=πd24
∴  Δρρ=2Δdd+ΔVV+ΔII+Δℓℓ
Δρρ=20.015.00+0.15.0+0.012.00+0.110.0
Δρρ=0.004+0.02+0.005+0.01
Δρρ=0.039
% error =Δρρ×100=0.039×100=3.90%.

Asked in: JEE Main 2021 (18 Mar Shift 1)

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