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I need help with An electric current is passed through a circuit containing two wires of the same material, connected in parallel. If the lengths and radii of the wires are in the ratio of 4/3 and 2/3 then the ratio of the currents passing through t

An electric current is passed through a circuit  containing two wires of the same material, connected in parallel. If the lengths and radii of the wires are in the ratio of 4/3 and 2/3    then the ratio of the currents passing through the wire will be

  • Option 1)

    3

  • Option 2)

    1/3

  • Option 3)

    8/9

  • Option 4)

    2

 
Answers (2)
557 Views
N neha

As we learnt in

Resistivity -

R=\rho\frac{l}{A}

- wherein

\rho\rightarrow  resistivity / specific resistance

 

 V=I_{1}R_{1}=I_{1}\:\rho\frac{l_{1}}{\pi r_{1}^{2}}

V=I_{2}R_{2}=I_{2}\:\rho\frac{l_{1}}{\pi r_{2}^{2}}

\frac{I_{1}}{I_{2}}=(\frac{l_{2}}{l_{1}})(\frac{r_{1}}{r_{2}})

\frac{I_{1}}{I_{2}}=\left ( \frac{3}{4} \right )\left ( \frac{2}{3} \right )^{2}=\frac{3\times 4}{4\times 9}=\frac{1}{3}


Option 1)

3

This option is incorrect.

Option 2)

1/3

This option is correct.

Option 3)

8/9

This option is incorrect.

Option 4)

2

This option is incorrect.

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