A conductor wire having 1029 free electrons/m3 carries a current of 20 A. If the cross-section of the wire is 1 mm2, then the drift velocity of electrons will be ....... (e = 1.6 ×10-19C).

Question

A conductor wire having 1029 free electrons/m3 carries a current of 20 A. If the cross-section of the wire is 1 mm2, then the drift velocity of electrons will be ....... (e = 1.6 ×10-19C). (A) 12.5 × 10-3 ms-1 (B) 1.25 × 10-4 ms-1 (C) 1.25 × 10-5 ms-1 (D) 1.25 ×10-3 ms-1

Tardigrade Admin · Accepted Answer

Current, l=20 A Free electron density, n =1029 Cross-sectional area of wire, A=1 mm 2=10-6 m 2 Magnitude of charge on an electron, e=1.6 × 10-19 C We know that, current, I = neAv d ⇒ vd=(1/n e A)=(20/1029 × 1.6 × 10-19 × 10-6) ⇒ v d =1.25 × 10-3 m / s

Q. A conductor wire having $1 0^{29}$ free electrons/ $m^{3}$ carries a current of $20 A$ . If the cross-section of the wire is $1 m m^{2}$ , then the drift velocity of electrons will be .......
$(e = 1.6 \times 1 0^{- 19} C) .$

$12.5 \times 1 0^{- 3} m s^{- 1}$

$1.25 \times 1 0^{- 4} m s^{- 1}$

$1.25 \times 1 0^{- 5} m s^{- 1}$

$1.25 \times 1 0^{- 3} m s^{- 1}$

Q. A conductor wire having 1029 free electrons/m3 carries a current of 20A. If the cross-section of the wire is 1mm2, then the drift velocity of electrons will be ....... (e=1.6×10−19C).

12.5×10−3ms−1

1.25×10−4ms−1

1.25×10−5ms−1

1.25×10−3ms−1

Current, l=20A Free electron density, n=1029 Cross-sectional area of wire, A=1mm2=10−6m2 Magnitude of charge on an electron, e=1.6×10−19C We know that, current, <br/>I=neAvd​<br/> <br/>⇒vd​=neA1​=1029×1.6×10−19×10−620​<br/> <br/>⇒vd​=1.25×10−3m/s<br/>

Q. A conductor wire having $1 0^{29}$ free electrons/ $m^{3}$ carries a current of $20 A$ . If the cross-section of the wire is $1 m m^{2}$ , then the drift velocity of electrons will be .......
$(e = 1.6 \times 1 0^{- 19} C) .$

$12.5 \times 1 0^{- 3} m s^{- 1}$

$1.25 \times 1 0^{- 4} m s^{- 1}$

$1.25 \times 1 0^{- 5} m s^{- 1}$

$1.25 \times 1 0^{- 3} m s^{- 1}$