JEE MainPhysicsCurrent ElectricityMCQ+4 / −1
An electric current is passed through a circuit containing two wires of the same material, connected in parallel. If the lengths and radii are in the ratio of and , then the ratio of the current passing through the wires will be
- A
- B
- C
- D
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Correct answer: B
- Use resistance formula
For a wire of length and radius , resistance is where is the resistivity.
So, for wires of the same material.
- Given ratios
Let the two wires be 1 and 2.
Length ratio: Radius ratio:
- Find resistance ratio
Since we get
Substitute the given ratios:
Thus,
- Use parallel connection condition
In parallel, both wires have the same potential difference. Hence current is inversely proportional to resistance:
Therefore,
So the ratio of currents is
- Match with options
The correct option is: which is Option B.
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