A tungsten wire in a 1.20x10^3 W heater has a cross sectional area of .014mm^2 and has a potential difference of 120 V, from end to end at 20 degree Celsius. What is the length of the wire?
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power P = V^2 / R = V^2 / (rho) L / A = V^2 A / (rho) L
so that length of the wire L = V^2 A / (rho) P, here given V= 120 V, A = 0.14 x10^-6m^2 P = 1200 W
and get the value of resistitvity 'rho' of Tungsten from tables, substitute all the values and solve to get L. o.k
so that length of the wire L = V^2 A / (rho) P, here given V= 120 V, A = 0.14 x10^-6m^2 P = 1200 W
and get the value of resistitvity 'rho' of Tungsten from tables, substitute all the values and solve to get L. o.k