Answer:
this is violation of II law of thermodynamics
Explanation:
As per 2nd law of thermodynamics we know that heat always flows from high temperature to low temperature
If heat flows from low temperature to high temperature then it is only possible when some external work is done on the system
So here it says that initially two blocks are at 10 degree C and 20 degree C
Now the cool object will become cooler and hot object becomes hotter
which shows that heat is flowing from low temperature to high temperature
So this is violation of II law of thermodynamics