At room temperature, copper has free electron density of 8.4 × 1028 m- 3 . The electron drift velocity in a copper conductor of cross-sectional area 10- 6 m2 and carrying a current of 5.4 A , will be -

Question

At room temperature, copper has free electron density of 8.4 × 1028 m- 3 . The electron drift velocity in a copper conductor of cross-sectional area 10- 6 m2 and carrying a current of 5.4 A , will be - (A) 4 m s- 1 (B) 0.4 m s- 1 (C) 4 c m s- 1 (D) 0.4 m m s- 1

Tardigrade Admin · Accepted Answer

Use i=ne A vd ∴ vd=(i/n e A) vd = (5.4/8.4 × 1028 × 1.6 × 10- 19 × 10- 6) vd = (5.4 × 10- 3/8.4 × 1.6) vd = 0.4 m m s- 1

Q. At room temperature, copper has free electron density of $8.4 \times 1 0^{28} m^{- 3}$ . The electron drift velocity in a copper conductor of cross-sectional area $1 0^{- 6} m^{2}$ and carrying a current of $5.4 A$ , will be -

$4 m s^{- 1}$

$0.4 m s^{- 1}$

$4 c m s^{- 1}$

$0.4 mm s^{- 1}$

Use $i = n e A v_{d}$
$∴ v_{d} = \frac{i}{n e A}$
$v_{d} = \frac{5.4}{8.4 \times 1 0 ^{28} \times 1.6 \times 1 0 ^{- 19} \times 1 0 ^{- 6}}$
$v_{d} = \frac{5.4 \times 1 0 ^{- 3}}{8.4 \times 1.6}$
$v_{d} = 0.4 mm s^{- 1}$

Q. At room temperature, copper has free electron density of 8.4×1028m−3 . The electron drift velocity in a copper conductor of cross-sectional area 10−6m2 and carrying a current of 5.4A , will be -

4ms−1

0.4ms−1

4cms−1

0.4mms−1