00. Electric Current, Current Density and Drift Velocity
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Current Electricity

151773 For mobile charge carries of mass $m$, the mobility is :

1 Independent of $m$
2 Directly proportional to $\mathrm{m}^{2}$
3 Inversely proportional to $\mathrm{m}$
4 Directly proportional to $\mathrm{m}$
Current Electricity

151774 A current of $2 \mathrm{~A}$ is passing through a metal wire of cross-sectional area $2 \times 10^{-6} \mathrm{~m}^{2}$. If the number density of free electrons in the wire is 5 $\times 10^{26} \mathrm{~m}^{-3}$, the drift speed of electrons is
(Given, $\mathrm{e}=1.6 \times 10^{-19} \mathrm{C}$ )

1 $\frac{1}{32} \mathrm{~ms}^{-1}$
2 $\frac{1}{16} \mathrm{~ms}^{-1}$
3 $\frac{1}{40} \mathrm{~ms}^{-1}$
4 $\frac{1}{80} \mathrm{~ms}^{-1}$
Current Electricity

151775 A conductor wire having $10^{29}$ electrons/ $\mathrm{m}^{3}$ carries a current of $20 \mathrm{~A}$. If the cross-section of the wire is $1 \mathrm{~mm}^{2}$, then the drift velocity of electrons will be :
$\left(\mathrm{e}=1.6 \times 10^{-19} \mathrm{C}\right)$

1 $1.25 \times 10^{-4} \mathrm{~ms}^{-1}$
2 $1.25 \times 10^{-3} \mathrm{~ms}^{-1}$
3 $1.25 \times 10^{-5} \mathrm{~ms}^{-1}$
4 $6.25 \times 10^{-3} \mathrm{~ms}^{-1}$
Current Electricity

151780 If the electric current through an electric bulb is $3.2 \mathrm{~A}$, the number of electrons flow through it in one second is

1 $2 \times 10^{9}$
2 $2 \times 10^{19}$
3 $3.2 \times 10^{9}$
4 $1.6 \times 10^{18}$
Current Electricity

151773 For mobile charge carries of mass $m$, the mobility is :

1 Independent of $m$
2 Directly proportional to $\mathrm{m}^{2}$
3 Inversely proportional to $\mathrm{m}$
4 Directly proportional to $\mathrm{m}$
Current Electricity

151774 A current of $2 \mathrm{~A}$ is passing through a metal wire of cross-sectional area $2 \times 10^{-6} \mathrm{~m}^{2}$. If the number density of free electrons in the wire is 5 $\times 10^{26} \mathrm{~m}^{-3}$, the drift speed of electrons is
(Given, $\mathrm{e}=1.6 \times 10^{-19} \mathrm{C}$ )

1 $\frac{1}{32} \mathrm{~ms}^{-1}$
2 $\frac{1}{16} \mathrm{~ms}^{-1}$
3 $\frac{1}{40} \mathrm{~ms}^{-1}$
4 $\frac{1}{80} \mathrm{~ms}^{-1}$
Current Electricity

151775 A conductor wire having $10^{29}$ electrons/ $\mathrm{m}^{3}$ carries a current of $20 \mathrm{~A}$. If the cross-section of the wire is $1 \mathrm{~mm}^{2}$, then the drift velocity of electrons will be :
$\left(\mathrm{e}=1.6 \times 10^{-19} \mathrm{C}\right)$

1 $1.25 \times 10^{-4} \mathrm{~ms}^{-1}$
2 $1.25 \times 10^{-3} \mathrm{~ms}^{-1}$
3 $1.25 \times 10^{-5} \mathrm{~ms}^{-1}$
4 $6.25 \times 10^{-3} \mathrm{~ms}^{-1}$
Current Electricity

151780 If the electric current through an electric bulb is $3.2 \mathrm{~A}$, the number of electrons flow through it in one second is

1 $2 \times 10^{9}$
2 $2 \times 10^{19}$
3 $3.2 \times 10^{9}$
4 $1.6 \times 10^{18}$
Current Electricity

151773 For mobile charge carries of mass $m$, the mobility is :

1 Independent of $m$
2 Directly proportional to $\mathrm{m}^{2}$
3 Inversely proportional to $\mathrm{m}$
4 Directly proportional to $\mathrm{m}$
Current Electricity

151774 A current of $2 \mathrm{~A}$ is passing through a metal wire of cross-sectional area $2 \times 10^{-6} \mathrm{~m}^{2}$. If the number density of free electrons in the wire is 5 $\times 10^{26} \mathrm{~m}^{-3}$, the drift speed of electrons is
(Given, $\mathrm{e}=1.6 \times 10^{-19} \mathrm{C}$ )

1 $\frac{1}{32} \mathrm{~ms}^{-1}$
2 $\frac{1}{16} \mathrm{~ms}^{-1}$
3 $\frac{1}{40} \mathrm{~ms}^{-1}$
4 $\frac{1}{80} \mathrm{~ms}^{-1}$
Current Electricity

151775 A conductor wire having $10^{29}$ electrons/ $\mathrm{m}^{3}$ carries a current of $20 \mathrm{~A}$. If the cross-section of the wire is $1 \mathrm{~mm}^{2}$, then the drift velocity of electrons will be :
$\left(\mathrm{e}=1.6 \times 10^{-19} \mathrm{C}\right)$

1 $1.25 \times 10^{-4} \mathrm{~ms}^{-1}$
2 $1.25 \times 10^{-3} \mathrm{~ms}^{-1}$
3 $1.25 \times 10^{-5} \mathrm{~ms}^{-1}$
4 $6.25 \times 10^{-3} \mathrm{~ms}^{-1}$
Current Electricity

151780 If the electric current through an electric bulb is $3.2 \mathrm{~A}$, the number of electrons flow through it in one second is

1 $2 \times 10^{9}$
2 $2 \times 10^{19}$
3 $3.2 \times 10^{9}$
4 $1.6 \times 10^{18}$
Current Electricity

151773 For mobile charge carries of mass $m$, the mobility is :

1 Independent of $m$
2 Directly proportional to $\mathrm{m}^{2}$
3 Inversely proportional to $\mathrm{m}$
4 Directly proportional to $\mathrm{m}$
Current Electricity

151774 A current of $2 \mathrm{~A}$ is passing through a metal wire of cross-sectional area $2 \times 10^{-6} \mathrm{~m}^{2}$. If the number density of free electrons in the wire is 5 $\times 10^{26} \mathrm{~m}^{-3}$, the drift speed of electrons is
(Given, $\mathrm{e}=1.6 \times 10^{-19} \mathrm{C}$ )

1 $\frac{1}{32} \mathrm{~ms}^{-1}$
2 $\frac{1}{16} \mathrm{~ms}^{-1}$
3 $\frac{1}{40} \mathrm{~ms}^{-1}$
4 $\frac{1}{80} \mathrm{~ms}^{-1}$
Current Electricity

151775 A conductor wire having $10^{29}$ electrons/ $\mathrm{m}^{3}$ carries a current of $20 \mathrm{~A}$. If the cross-section of the wire is $1 \mathrm{~mm}^{2}$, then the drift velocity of electrons will be :
$\left(\mathrm{e}=1.6 \times 10^{-19} \mathrm{C}\right)$

1 $1.25 \times 10^{-4} \mathrm{~ms}^{-1}$
2 $1.25 \times 10^{-3} \mathrm{~ms}^{-1}$
3 $1.25 \times 10^{-5} \mathrm{~ms}^{-1}$
4 $6.25 \times 10^{-3} \mathrm{~ms}^{-1}$
Current Electricity

151780 If the electric current through an electric bulb is $3.2 \mathrm{~A}$, the number of electrons flow through it in one second is

1 $2 \times 10^{9}$
2 $2 \times 10^{19}$
3 $3.2 \times 10^{9}$
4 $1.6 \times 10^{18}$