Share

# When 5 V Potential Difference is Applied Across a Wire of Length 0.1 m, the Drift Speed of Electrons is 2.5 X 10-4 M/S. If the Electron Density in the Wire is 8 X 10^28 m^-3, Calculate the Resistivity of the Material of the Wire. - CBSE (Science) Class 12 - Physics

ConceptPotential Difference and Emf of a Cell

#### Question

When 5 V potential difference is applied across a wire of length 0.1 m, the drift speed of electrons is 2.5 x 10-4 m/s. If the electron density in the wire is 8 x 1028 m-3, calculate the resistivity of the material of the wire.

#### Solution

The drift speed is

v_d=I/(

Now, we know that the current is given from Ohm’s law as

I=V/R

:.v_d = V/

:.V/(

=>V/(

Now, resistivity is given as rho=(RA)/l

:.V/(

:.rho=5/(8xx10^28xx1.6xx10^(-19)xx2.5xx10^(-4)xx0.1)

∴ ρ = 1.56 x 10-5 Ωm

Is there an error in this question or solution?

#### APPEARS IN

Solution When 5 V Potential Difference is Applied Across a Wire of Length 0.1 m, the Drift Speed of Electrons is 2.5 X 10-4 M/S. If the Electron Density in the Wire is 8 X 10^28 m^-3, Calculate the Resistivity of the Material of the Wire. Concept: Potential Difference and Emf of a Cell.
S