Em is interpreted in three ways:
1. The mīm letter in the word em is considered a connection (ṣila, i.e., the hamza is taken as an interrogative particle, and the mīm as a connective particle); as in the following verses:
Or [em] were they created by nothing / without any cause?! (al-Ṭūr 52:35)
Here, the mīm letter is a ṣila; thus, the phrase em khuliqū min ghayri shay'in means a khuliqū min ghayri shay'in [Or were they created by nothing / without any cause?!].
Or [em] are daughters for Him?! (al-Ṭūr 52:39)
Here too, the mīm letter is a ṣila; (thus, the phrase em lahu'l-banātu means a lahu'l-banātu [Or are daughters for Him?!]).
2. Em is used in the sense of ḥattā, rather / on the contrary; as in the following verses:
Em {that is, rather} you utter a manifest word. (al-Raʿd 13:33)
Here, em does not mean "Or ... is it ...?" but rather [bal], and the phrase means "Rather, you utter a manifest word."
Em {that is, rather} I am better than him. (al-Zuhruf 43:12)
Here, em does not mean "Or ... am I not?" but rather [bal], and the phrase means "Rather, I am better than him."
They say, "Em {that is, rather} we are a group supporting each other." (al-Qamar 54:44)
Here too, em does not mean "Or ... are we ...?" but rather [bal], and the phrase means "Rather, we are a group supporting each other."
3. The particle em is also used as an interrogative particle in the sense of or / or else / or perhaps; as in the following verses:
Em {that is, or} do you feel secure against Him who is in the heaven that He will not send upon you a deadly storm?! (al-Mulk 67:17)
Em {that is, or} will He return you to it again... (al-Isrāʾ 17:69)