Question

100mg mass of nichrome metal is drawn into a wire of area .05 mm2. Calculate resistance if density is 8.4+10^3 resistivity is 1.2×10^6

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