(B) Given: Current $i = 10\, A$,Area $A = 5\, mm^{2} = 5 \times 10^{-6}\, m^{2}$,Drift velocity $v_{d} = 2 \times 10^{-3}\, m/s$,and charge of an elec

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(B) Given: Current $i = 10\, A$,Area $A = 5\, mm^{2} = 5 \times 10^{-6}\, m^{2}$,Drift velocity $v_{d} = 2 \times 10^{-3}\, m/s$,and charge of an electron $e = 1.6 \times 10^{-19}\, C$.We know the relation between current and drift velocity is $i = neAv_{d}$.Rearranging for the number density $n$,we get $n = \frac{i}{eAv_{d}}$.Substituting the values: $n = \frac{10}{1.6 \times 10^{-19} \times 5 \times 10^{-6} \times 2 \times 10^{-3}}$.$n = \frac{10}{16 \times 10^{-28}} = 0.625 \times 10^{28} = 625 \times 10^{25}\, m^{-3}$.

Class 12 Physics Current Electricity Current Density, Drift Velocity and Mobility

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

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A
$2 \times 10^{6}$
B
$625 \times 10^{25}$
C
$2 \times 10^{25}$
D
$1 \times 10^{23}$

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Current Electricity

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Current Density, Drift Velocity and Mobility

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Medium

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

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$A$ cylindrical wire of radius $0.5 \, mm$ and conductivity $5 \times 10^{7} \, S/m$ is subjected to an electric field of $10 \, mV/m$. The expected value of current in the wire will be $x^{3} \, \pi \, mA$. The value of $x$ is ......

MediumJEE MAIN 2021

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When a potential difference is applied across the ends of a linear metallic conductor,

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There are $0.8 \times 10^{23}$ free electrons $/ cm^3$ in copper. If a $0.2 \, A$ current is flowing in a copper wire, then the drift velocity of electrons will be, given the cross-sectional area of the wire is $0.01 \, cm^2$.

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

Similar Questions

For a cylinder of radius $R$,the current density is given by $J = J_0 \frac{r}{R}$,where $J_0$ is a constant and $r$ is the distance from the axis. Calculate the total current.

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

$A$ cylindrical wire of radius $0.5 \, mm$ and conductivity $5 \times 10^{7} \, S/m$ is subjected to an electric field of $10 \, mV/m$. The expected value of current in the wire will be $x^{3} \, \pi \, mA$. The value of $x$ is ......

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There are $0.8 \times 10^{23}$ free electrons $/ cm^3$ in copper. If a $0.2 \, A$ current is flowing in a copper wire, then the drift velocity of electrons will be, given the cross-sectional area of the wire is $0.01 \, cm^2$.

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