Drift Velocity, Mobility and Their Relation with Electric Current

The drift velocity of electrons for a conductor connected in an electrical circuit is $V_d$. The conductor is now replaced by another conductor with same material and same length but double the area of cross-section. The applied voltage remains same. The new drift velocity of electrons will be

A current of $10 \mathrm{A}$ exists in a wire of cross-sectional area of $5{ \mathrm{mm}}^2$ with a drift velocity of $2\times {10}^{-3}{ \mathrm{m} \mathrm{s}}^{-1}.$ The number of free electrons in each cubic meter of the wire is

A current of $5\mathrm{ }\mathrm{A}$ passes through a copper conductor (resistivity $=1.7\times {10}^{-8}\mathrm{ }\mathrm{\Omega }\mathrm{ }\mathrm{m}$ ) of radius of cross-section $5\mathrm{ }\mathrm{m}\mathrm{m}$ . Find the mobility of the charges if their drift velocity is $1.1\times {10}^{-3}\mathrm{ }\mathrm{m} {\mathrm{s}}^{-1}$ .

Drift speed of electrons, when $1.5 \mathrm{A}$ current flows in a copper wire of cross section $5 {\mathrm{mm}}^2$ is $v_d.$ If the electron density in copper is $9\times {10}^{28} {\mathrm{m}}^{-3}$ the value of $v_d$ in $\mathrm{mm} {\mathrm{s}}^{-1}$ is close to (Take charge of an electron to be $=1.6\times {10}^{-19} \mathrm{C}$)

Suppose the drift velocity $v_d$ in a material varied with the applied electric field E as $v_{d }\propto \sqrt{E}$. Then $V-I$ graph for a wire made of such a material is best given by:

When $5 \mathrm{V}$ potential difference is applied across a wire of length $0.1 \mathrm{m}$, the drift speed of electrons is $2.5\times {10}^{-4} \mathrm{m} {\mathrm{s}}^{-1}$ . If the electron density in the wire is $8\times {10}^{28} {\mathrm{m}}^{-3}$ , the resistivity of the material is close to: