A copper wire of 3 mm2 cross-sectional area carries a current 5A . The magnitude of the drift velocity for the electrons in the wire is (Assume each copper atom contributes one free electron and density of copper =8920 kgm- 3 , MCu=63.5kgmol- 1 )

Question

A copper wire of 3 mm2 cross-sectional area carries a current 5A . The magnitude of the drift velocity for the electrons in the wire is (Assume each copper atom contributes one free electron and density of copper =8920 kgm- 3 , MCu=63.5kgmol- 1 ) (A) 0.24ms- 1 (B) 0.12 m s- 1 (C) 2.4ms- 1 (D) 0.06ms- 1

Tardigrade Admin · Accepted Answer

Given, A=3× 10- 6m2,I=5A, MCu=63.5kgmol- 1 ρ C u=8920kgm- 3 Electron density =(6.023 × 1023 × 8920/63.5) =8.46× 1025m- 3 ∴ Drift velocity, vd=(I/e n A) =(5/1.6 × 10- 19 × 8.46 × 1025 × 3 × 10- 6) =(5/40.608) =0.12ms- 1

Q. A copper wire of $3 m m^{2}$ cross-sectional area carries a current $5 A$ . The magnitude of the drift velocity for the electrons in the wire is (Assume each copper atom contributes one free electron and density of copper $= 8920 k g m^{- 3}$ , $M_{C u} = 63.5 k g m o l^{- 1}$ )

$0.24 m s^{- 1}$

$0.12 m s^{- 1}$

$2.4 m s^{- 1}$

$0.06 m s^{- 1}$

Q. A copper wire of 3mm2 cross-sectional area carries a current 5A . The magnitude of the drift velocity for the electrons in the wire is (Assume each copper atom contributes one free electron and density of copper =8920kgm−3 , MCu​=63.5kgmol−1 )

0.24ms−1

0.12ms−1

2.4ms−1

0.06ms−1

Given, A=3×10−6m2,I=5A, MCu​=63.5kgmol−1 ρCu​=8920kgm−3 Electron density =63.56.023×1023×8920​ =8.46×1025m−3 ∴ Drift velocity, vd​=enAI​ =1.6×10−19×8.46×1025×3×10−65​ =40.6085​ =0.12ms−1

Q. A copper wire of $3 m m^{2}$ cross-sectional area carries a current $5 A$ . The magnitude of the drift velocity for the electrons in the wire is (Assume each copper atom contributes one free electron and density of copper $= 8920 k g m^{- 3}$ , $M_{C u} = 63.5 k g m o l^{- 1}$ )

$0.24 m s^{- 1}$

$0.12 m s^{- 1}$

$2.4 m s^{- 1}$

$0.06 m s^{- 1}$