A metallic wire of cross sectional area 4 mm2 carries a current of 3.2 A . If 5 × 1026 charge carriers flow across the wire per unit volume, then their drift velocity in m s-1 is

Question

A metallic wire of cross sectional area 4 mm2 carries a current of 3.2 A . If 5 × 1026 charge carriers flow across the wire per unit volume, then their drift velocity in m s-1 is (A)  1  (B)  0.1  (C)  0.01  (D)  10

Tardigrade Admin · Accepted Answer

Here,
Cross-sectional area of the wire,

A = 4 m m^{2} = 4 \times 1 0^{- 6} m^{2}

Current flowing through the wire ,

I = 3.2 A

Number of charge carriers per unit volume of the wire (number density),

n = 5 \times 1 0^{26} m^{- 3}

The drift velocity is

v_{d} = \frac{I}{n e A} = \frac{( 3.2 A )}{( 5 \times 1 0 ^{26} m ^{- 3} ) ( 1.6 \times 1 0 ^{- 19} C ) ( 4 \times 1 0 ^{- 6} m ^{2} )}

= 0.01 m s^{- 1}

Q. A metallic wire of cross sectional area $4 m m^{2}$ carries a current of $3.2 A$ . If $5 \times 1 0^{26}$ charge carriers flow across the wire per unit volume, then their drift velocity in $m s^{- 1}$ is

$1$

$0.1$

$0.01$

$10$

Q. A metallic wire of cross sectional area 4mm2 carries a current of 3.2A . If 5×1026 charge carriers flow across the wire per unit volume, then their drift velocity in ms−1 is

1

0.1

0.01

10

Here, Cross-sectional area of the wire, A=4mm2=4×10−6m2 Current flowing through the wire , I=3.2A Number of charge carriers per unit volume of the wire (number density), n=5×1026m−3 The drift velocity is vd​=neAI​=(5×1026m−3)(1.6×10−19C)(4×10−6m2)(3.2A)​ =0.01ms−1

Q. A metallic wire of cross sectional area $4 m m^{2}$ carries a current of $3.2 A$ . If $5 \times 1 0^{26}$ charge carriers flow across the wire per unit volume, then their drift velocity in $m s^{- 1}$ is

$1$

$0.1$

$0.01$

$10$