With a test light.
Problem can be called as SAMASYA in hindi. It is the word if the person is in some kind of trouble.
It depends on the context of your question. Innocent people who aren't in trouble with the law don't have a 'problem'. If an innocent person is swept up into a legal difficulty, the biggest problem for the person is proving they are innocent.
You call a person that is causing trouble a trouble maker.
A person who has a sleeping problem is called an Insomniac.
Galileo discovered Saturn
It is when a person has trouble with nature or when nature makes trouble with the person.
Saturn has been known for thousands of years. No particular person discovered it.
Saturn has more gravity so it would crush a person.
A person who doesn't go out to find trouble yet finds themselves in trouble can be called a trouble magnet. Most trouble magnets unconsciously seek out trouble by associating with the wrong kind of people.
This is a person who lives on Saturn.
A 95 pound person would weigh 101 pounds on Saturn. Saturn's gravitational pull is very similar to the gravity on Earth.
If the person is trying to stay out of trouble, try telling them and involving them in activities that will keep him/her distracted from trouble.