Question

What length of a tungsten (p=5.5x1012.m) wire of .05 mm diameter is needed to make a 20-92 resistor? 6 pts.

Answer 1

Ans:- Resistivity of the tungsten P = 5.5X10 8 nm Resistance of the wire R = zon Diameter of the tungsten wire d = 0.05 mm. cross section area of the wire - A = T (9) 2= 3.148 (58 16-5 2 4 A = 1.964 10m. = 1.96 nm. Resistivity of a conductor is - P=RA , where l-length of the wire d = RA = 20 X 1.96 X10-9 P. 5.5x 10-8 1 l = 0.713 m. Hence length of the wire is 0.713 m.