Here are the personal nouns formed by adding appropriate suffixes to the given abstract nouns:

1. **Physics** → **Physicist**: a licensed medical practitioner
2. **Mathematics** → **Mathematician**: a person skilled in mathematics
3. **Guard** → **Guardian**: a person who cares for persons or property
4. **Drama** → **Dramatist**: someone who writes plays
5. **Dentistry** → **Dentist**: a person qualified to practice dentistry
6. **Beauty** → **Beautician**: someone who works in a beauty parlour
7. **Assistance** → **Assistant**: a person who helps someone do his job, providing him with practical support
8. **Accounting** → **Accountant**: someone who maintains and audits business accounts

9. **Technology** → **Technologist**: a person who uses scientific knowledge to solve practical problems
10. **Serving** → **Servant**: a person working in the service of another
11. **Piano** → **Pianist**: a person who plays the piano
12. **Philosophy** → **Philosopher**: a specialist in philosophy, a wise person who is calm and rational
13. **Novel** → **Novelist**: someone who writes novels
14. **Nationalism** → **Nationalist**: one who loves and is prepared to defend his or her country
15. **Music** → **Musician**: someone who plays a musical instrument as a profession
16. **Biology** → **Biologist**: a scientist who studies living organisms
17. **Environment** → **Environmentalist**: someone who works to protect the environment from destruction or pollution
18. **Electric** → **Electrician**: a person who installs or repairs electrical or telephone lines
19. **Economy** → **Economist**: an expert in the science of economics
20. **Cycle** → **Cyclist**: a person who rides a bicycle