Q. 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 raio $4 / 3$ and $2 / 3$, then the ratio of the currents passing through the wires will be

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A

$8 / 9$

B

$1 / 3$

C

3

D

2

Solution:

we know that in parallel combination, maximum current flows along the least resistance .
so $I_{1} / I_{2}=R_{2} / R_{1}$
$=l_{2} / A_{2} \times A_{1} / l_{1}$
$=l_{2} / l_{1} \times A_{1} / A_{2}$
$=3 / 4 \times 2^{2} / 3^{2}$
$=3 / 4 \times 4 / 9=1 / 3$.

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