Heating Elements Of Alloys?

heating in electrical appliances is based on the joule's law...formula h=i^2 *rt ,whr h is heat,i is current,r is resistance n t is time... so heat is proportional to resistance also r=pl/a ,whr p is resistivity,l is length, n a is area... therefore from the two equatns heat is proportional to resistivity n alloys have a higher resistivity than pure metals. So............