At a certain temperature T1, a (1.717x10^2) mm rod of a copper-nickel alloy has a resistivity of (2.7000x10^-7) ?-m. For pure copper, the resistivity at 0°C is 1.58 x 10-8 ?-m and the change in resistivity per degree increase in temperature is 6.50 x 10-11 (?-m)/°C. The value of A for nickel in copper is 1.18 x 10-6 ?-m and the coefficient of thermal expansion of this alloy is (1.5470x10^-5) (°C)-1.
If the resistivity of this alloy is dependent only on thermal and impurity considerations, find the composition of this alloy (in at% Ni) if the rod increases in length by (4.9890x10^-1) mm when heated from T1 to (1.86x10^2) °C.
As always, use scientific notation in the form X.YZ x10^n
Note: Your answer is assumed to be reduced to the highest power possible.