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Help me understand! - Current Electricity - JEE Main-5

A current of 5 A  passes through a copper conductor ( Resistivity = 1.7 \times 10^{-8}\Omega m)

of radius of cross-section 5mm. Find the mobility of the charges if their drift velocity is 1.1 \times 10^{-3} m/s.

  • Option 1)

    1.8m^{2}/Vs

  • Option 2)

    1.5m^{2}/Vs

  • Option 3)

    1.3m^{2}/Vs

  • Option 4)

    1.0m^{2}/Vs

 
Answers (1)
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Mobility -

\mu =\frac{v_{d}}{E}

- wherein

\mu- Mobility

v_{d}- Drift velocity

 

 

V_d=\mu E=\mu (\frac{V}{l})=1.1\times 10^{-3}m/s

\rho =1.7\times 10^{-8}

I=5 A

V_d=\mu (\frac{V}{l})=\frac{\mu (IR)}{l}=\mu \frac{I}{l}\times \rho \frac{l}{A}

V_d=\frac{\mu \cdot I\cdot \rho }{A}

\mu =\frac{V_d\cdot A}{I\cdot \rho }=\frac{1.1\times 10^{-3}\times 3.14\times 25\times 10^{-6}}{5\times 1.7\times 10^{-8}}

\mu =1m^{2}/Vs


Option 1)

1.8m^{2}/Vs

Option 2)

1.5m^{2}/Vs

Option 3)

1.3m^{2}/Vs

Option 4)

1.0m^{2}/Vs

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