Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 12

# Calculate the Electric Field in a Copper Wire of Cross-sectional Area 2.0 Mm2 Carrying a Current of 1 A. the Resistivity of Copper = 1.7 × 10–8 ω M - Physics

Sum

Calculate the electric field in a copper wire of cross-sectional area 2.0 mm2 carrying a current of 1 A.
The resistivity of copper = 1.7 × 10–8 Ω m

#### Solution

Given:-

Area of cross-section, A = 2 × 10–6 m2

Current through the wire, i = 1 A

Resistivity of copper, ρ = 1.7 × 10–8 Ωm

Resistance of a wire,

$R = \rho\frac{l}{A}$

Also from Ohm's Law, voltage across a wire,

$V = iR = \frac{i\rho l}{A}$

The electric field of the wire,

$E = \frac{V}{l}$

$\Rightarrow E = \frac{i\rho l}{Al} = \frac{i\rho}{A}$

$\Rightarrow E = \frac{1 \times 1 . 7 \times {10}^{- 8}}{2 \times {10}^{- 6}}$

$\Rightarrow E = 8 . 5 V/m$

Concept: Ohm's Law
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#### APPEARS IN

HC Verma Class 11, Class 12 Concepts of Physics Vol. 2
Chapter 10 Electric Current in Conductors
Exercises | Q 12 | Page 198