What is the object of preposition in following sentence Lets meet Naomi and Sam at ten oclock.?

The object of the preposition "at" in the sentence "Let's meet Naomi and Sam at ten o'clock" is ten o'clock.

Here's why:

* Preposition: "at"

* Object of the preposition: The noun or pronoun that follows the preposition and answers the question "What?" or "Whom?"

* In this case: "ten o'clock" is the noun phrase that follows "at" and answers the question "At what time?"

Therefore, "ten o'clock" is the object of the preposition "at".