Actually, there are not that big difference between them, but 긴장-하다 is the exact present verb form. if you use -하다 form in verb, there are some focus on to the Subject who/which do something. 긴장-되다 is a pp form like "being nervoused". It is using in more situation like "나는 ~때문에 긴장돼." -> In this example, we used -되다 form because we mentioned specific reason for being nervoused. Same thing for 걱정하다 and 걱정되다.