//example-22.11 //page no-674 //given //depth of penetration at 3K is 39.8 nm and at 7.1 K is 1730 A T1=3 //K T2=7.1 //K dp1=39.6*10^-9 //m dp2=1730*10^-10 //m //as we know that depth of penetration and temp are related as //(dp(T)/dp(T0))=1/(1-t^4/Tc^4) //so we get //at 3K //let dp(T0)=dp0 //dp0=sqrt(dp1^2*(1-T1^4/Tc^4)) -(1) //also //dp0=sqrt(dp2^2*(1-T2^4/Tc^4)) .----(2) //solving 1 and 2 we get //((Tc^4-81)/(Tc^4-(7.1)^4))=(173)^2/(39.6)^2 //so we get Tc=(48417.9/18.085)^(1/4) //K\ //depth of penetration at absolute zero willbe dp0=sqrt(dp1^2*(1-T1^4/Tc^4))*10^9 //nm printf ("critica temp is %f K\n and depth of penetration at critica zero is %f nm",Tc,dp0)