Question

Find the area of cross-section of the wire which when connected across the potential difference of 150 volts, produce a current of 5 milli ampere. It is given that the length of the wire is 20 centimeter and resistivity is 10 ohm-centimeter. 3 ​

Answer 1

Resistance of the wire = (Potential drop driving the current in the wire)/(current flowing through the wire) = 2.0 V/ 4 amp. =0.5 Ohm.

Now resistance R of a wire of length l and area of cross-section a = (resistivity) × l/ a.

In our case length l = 50 cm, and area of cross-section a = 1 mm² = 0.01 cm²

So,

0.5 Ohm = (resistivity) × 50 cm/ 0.01 cm² = (resistivity)× 50 × 100 /cm = (resistivity) × ( 5000/cm)

==> Resistivity = 1 × 10^- 4 Ohm- cm.

Answer 2

Answer:

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Explanation:

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