Internal Fragmentation :- It is unused space inside a partition area.
When we divide 128 MB to equal size partitions each of 16MB . We are left with Blocks Each of 16MB
Now 2 process Came .
- 1st process occupies 12MB out of 16 MB of a partition Space Left = 4MB
- 2nd process occupies 6MB out of 10MB of another partition . Space Left = 10MB
% of internal Fragmentation will be $\left ( \frac{4}{16} + \frac{10}{16} \right ) \times 100$ = 87.5%