When you post something on your News Feed:
When you post text, photos, links, etc. on your news feed, all of your followers can see that post. If your post gets likes it will still only be visible to your followers.
If you post something on a Topic Page:
When you post text, photos, links, etc. on a Topic Page, all followers of that topic will be able to see that post.
No one can see a list of the posts you have liked and/or commented on. Other users don't get notified when you like or comment on a post, unless they published that post themselves.