What is the difference between Percocet 10 and Oxycodone 15?

I know I had the Percocet years ago and it sort of made me sick. My husband is on the Oxycodone 15mg for a spinal injury and they are so much smaller but stronger. My doctor is referring me back to pain management and I want to have my answers ready when I see the doctor. Does someone know the actual real answer?