what is the effect on PPC when there is massive unemployment? How about, when there is underemployment? Are they both the same?

Dear Student

• Massive unemployment implies that people who were previously employed, are now unemployment.
• Underemployment implies that people are working below their capacity.

In both these situations, the economy would be producing at a level below the PPC, i.e., inside the PPC.
Hope this information clarifies your doubts. Keep posting :-)
Regards