There is a current of 112 pA when a certain potential is applied across a certain resistor. When that same potential is applied across a resistor made of the identical material but 25 times longer, the current is 0.044 pA. Compare the effective diameters of the two resistors.

Explanation:

Given :

Current in first wire A

Current in second wire A

Length of first wire =

Length of second wire =

Here potential across a resistor is same.

From ohm's law,

Where resistance of the wire,

Resistor of wire is given by,

Where cross section area of the wire =

We write area in terms of diameter

Now we have to compare current in both wires,

Put the value of resistor in terms of its diameter,

      ≅ 10

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