\(\frac{{{{\left( {\frac{{\Delta Q}}{t}} \right)}_1}}}{{{{\left( {\frac{{\Delta Q}}{t}} \right)}_2}}} = \frac{{\Delta {\theta _2}}}{{\Delta {\theta _1}}}\)
==> \(\frac{{60}}{{{{\left( {\frac{{\Delta Q}}{t}} \right)}_2}}} = \frac{{80 - 20}}{{40 - 20}}\)
==> \({\left( {\frac{{\Delta Q}}{t}} \right)_2} = \frac{{20\,cal}}{{sec}}\)