Preferential cooking

If you take Channa dal and Moong dal, any cook will tell you, that Channa dal takes much longer to get cooked. Say 5 whistles. Whereas Moong dal can get cooked in 3. Now in case you want to make mixed dal, and put both of them together in a cooker, even if you give 5 whistles, you find that Channa dal is not cooked, and Moong dal is (naturally) over cooked, almost ground. Why is that Channa dal didn't get the required heat, even after giving 5 whistles!?

The very fact that Channa dal takes longer to cook, implies that it has less heat capacity. When we supply the heat to the mixture, the Moong dal with lower heat capacity absorbs more heat than Channa dal, and Channa dal remains un-cooked !