Question

A current of 1.8A flows through a wire of area of cross section 0.5 mm sq .find the current density in the wire .if the no. Density of electrons in the wire is 8.8×10 the power 28 m per cube , find tge drift velocity of electrons.

Answer 1

I thick it will help u .

Answer 2

Answer:

Current density= 3.6 × 10³ Am⁻²

Drift velocity = 0.25 × 10⁻⁶ ms⁻¹

Explanation:

As per the given question,

We have given

Current, I = 1.8 A

Area, A = 0.5 mm²

No. of electrons = 8.8 × 10²⁸

As we know 1 e⁻ = 1.6 × 10⁻¹⁹ C

Formula used:

Current density(J) × Area = Current

$\Rightarrow\  J=\frac{I}{A}\\\Rightarrow\  J=\frac{1.8}{0.5\times 10^{-3}}$

⇒ J = 3.6 × 10³ Am⁻²

Drift velocity is given by

$V_{d}=\frac{I}{nAe^{-}}$

$\Rightarrow V_{d}=\frac{1.8}{8.8\times 10^{28} \times 0.5\times 10^{-3} \times 1.6\times 10^{-19}}$

Or

$V_{d}=0.255\times 10^{-6}\frac{m}{s}$