The year is 1985. You are on the ground floor of a four-story building. On the top floor there is a lightbulb. On the ground floor with you there are three light switches. All three switches are connected to electricity but only one of the switches controls the lightbulb on the top floor - the other two switches are not connected to anything.

You cannot go outside, there is no one helping you, and most importantly, you can only go up to the top floor one time to check.

How do you determine with absolute certainty which of the three switches controls the lightbulb?

If this post gets any traction I’ll post the answer.

The answer involves no wordplay, is not cheesy or impossible to figure out… just use logic and you should be able to come up with the correct answer.