Translation:Is professor Tini known by children?
No. That would be "Apakah anak-anak kenal profesor Tini?"
To be even more correct/formal, the meng- form of "kenal", "mengenal" should be used.
Note that "kenal" means to know in the sense having a certain level of aquaintance with someone or experience/exposure with/to something. "Tahu" should be used instead if you mean merely knowing who someone/something is.