Question

6. a) Two different wires (materials 1 & 2) have lengths 1 and 2 and associated diameters di and If the resistance R of the wires is to be the same show the relationship between their diameters is given by dz =d, P2h VPL b) Using the above result, determine the diameter of a nichrome wire (p=96 x 10 - Qm) of length 4 mifit is to have the same resistance has a copper wire (p=1.72 x 10- m) whose length is 10 m and whose diameter is 0.8 mm:

Answer 1

Resistance of a material is given by ROSA - 0 Where, pa resistivity d = length A - Area of cross-section ETTO) = 11d? (a = diameter) . R = 48.4 © - Tid if R = R2 45,4 11.2 - 422 12 110,2 idee di Sole Sili b) given, S₂ = 96x10hmi d2 = 4 m 3, = 1,72 x108_1m, l = 10m d, = 0.8 mm = 8x104 m using ③ , 196+10 + 4 de = 10.8mm) / "V 1.72410-8x10 =10.8 x 4.725) mm ~ 3.78 mm