When a second light bulb is wired into an electric circuit already containing one light bulb, the first one dims. What kind of circuit is the light bulb wired into?

open circuit!

Yes!

No. The bulb is wired into a SERIES circuit. If the first bulb did not dim and the second bulb burned as brightly as the first one, then it is a PARALLEL circuit. And if the bulbs are not burning at all, THEN there is an OPEN circuit. When the bulbs are burning there is a CLOSED circuit. I hope this helps.

I figured that after I posted my "Yas!" I graduated in Electrical Contruction...lol.

That's great! Congratulations on graduating in Electrical Construction! It sounds like you have a good understanding of circuits. If you have any more questions or need further explanations, feel free to ask!