When 5 V potential difference is applied across a wire of length 0.1 m, the drift speed of electrons is `2.5 xx 10^(-4) ms ^(-1)`. If the electron density in the wire is ` 8 xx 10^(28) m^(-3)`, the resistivity of the material is close to :A. `1.6 xx 10^(-6) Omega m`B. `1.6 xx 10^(-5) Omegam`C. `1.6 xx 10^(-8)Omega m `D. `1.6 xx 10^(-7) Omega m`

When 5 V potential difference is applied across a wire of length 0.1 m

1.	When 5 V potential difference is applied across a wire of length 0.1 m, the drift speed of electrons is `2.5 xx 10^(-4) ms ^(-1)`. If the electron density in the wire is ` 8 xx 10^(28) m^(-3)`, the resistivity of the material is close to :A. `1.6 xx 10^(-6) Omega m`B. `1.6 xx 10^(-5) Omegam`C. `1.6 xx 10^(-8)Omega m `D. `1.6 xx 10^(-7) Omega m`
Answer» Correct Answer - B (b) `V= IR = (neAv_d)rho l/A` `:. rho = V/(V_dline)` Here V = potential difference l = length of wire n = no. of electrons per uint volume of conductor. e = no. of electrons Placing the value of above parameters we get resistivity . `rho = (5/(8 xx 10^(28) xx 1.6 xx 10^(-19) xx 2.5 xx 10^(-4) xx 0.1))` `= 1.6 xx 10^(-5) Omegam`

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