The temperature coefficient of resistance of platinum is `alpha=3.92xx10^(-3)K^(-1)` at `0^(@)C`. Find the temperature at which the increase in the resistance of platinum wire is `10%` of its value of `0^(@)C`.

Explanation

Let resistance of the wire be `R_1 ` at `t_1^0 C (=0^@ C) `
At `t_2^0 C` resistance of the wire `R_2`
`R_2 =(110 R_1)/(100) = 1.1 R_1 , alpha = 3.92xx10^(-3) K^(-1)`
`Deltat = (R_2 - R_1)/(R_1 alpha) implies = (1.1 R_1 - R_1)/(R_1 alpha)`
`=(R_1(1.1-1))/(R_1 alpha) =(0.1 R_1)/(R_1 alpha) = (0.1)/(3.92xx10^(-3)) Deltat = 25.51^@ C`
`t_2 = 25.51 +0 = 25.51^@ C`