Temperature of a steel block changes from 80^(@)C to 75^(@)C in time t_(1), from 75^(@)C to 70^(@)C in time t_(2) and from 70^(@)C to 65^(@)C in time t_(3) then. . . . . . . . .

Temperature of a steel block changes from 80^(@)C to 75^(@)C in time t

1.	Temperature of a steel block changes from 80^(@)C to 75^(@)C in time t_(1), from 75^(@)C to 70^(@)C in time t_(2) and from 70^(@)C to 65^(@)C in time t_(3) then. . . . . . . . .
Answer» `t_(1)=t_(2)=t_(3)` `t_(1)ltt_(2)=t_(3)` `t_(1)ltt_(2)ltt_(3)` `t_(1)gtt_(2)gtt_(3)` Solution :According to Newton.s LAW of cooling, `(dQ)/(dt)` is PROPORTIONAL to the temperature differnce. It decreases as temperature decreases. So at high temperature, time is LESS for `5^(@)C` DECREASE in temperature and at LOWER temperature, time is more for `5^(@)C` decrease in temperature. `:.t_(1)lt t_(2) lt t_(3)`