Q. Limitation identified in Amdahls law?

There is one main limitation identified in Amdahl's law. As said by Amdahl's law workload or problem size is forever fixed as well as number of sequential operations mostly remains same. Which presumes that distribution of number of serial operations and parallel operations always remain same. This condition is displayed in Figure and ratio of sequential and parallel operations are independent of problem size. 

Figure: Fixed load for Amdahl's Law

Though practically number of parallel operations rises according to size of problem. As load is assumed to be fixed according to Amdahl's law execution time will continue decreasing whenever number of processors is increased. This condition is displayed in Figure below. This is Introduction to processes operation.

Figure: Execution Time decreases for Amdahl's Law