A current of 10   A exists in a wire of cross-sectional area of 5   mm 2 with a drift velocity of…

A current of 10 A exists in a wire of cross-sectional area of 5 mm2 with a drift velocity of 2×10-3 m s-1. The number of free electrons in each cubic meter of the wire is
  1. 2×106
  2. 625×1025
  3. 2×1025
  4. 1×1023

Solution

i=10 A, A=5 mm2=5×10-6 m2 and vd=2×10-3 m s-1

We know, i=neAvd

∴10=n×1.6×10-19×5×10-6×2×10-3

⇒n=0.625×1028=625×1025

Asked in: JEE Main 2021 (17 Mar Shift 1)

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