Kabl pripada električnom aparatu.

Pripada is the 3rd person singular present tense of pripadati. In this sentence, it means belongs.

So:

• Kabl pripada električnom aparatu.
• literally: The cable belongs to the electrical device.

This verb is commonly used when something belongs to someone or something, or is assigned to it.

Because pripadati requires the dative case.

The basic dictionary form is aparat:

• aparat = device, apparatus

But after pripadati, you use the dative singular:

• aparat → aparatu

So električnom aparatu means to the electrical device.

Because the adjective has to agree with the noun in gender, number, and case.

The noun aparat is:

• masculine
• singular
• here in the dative

So the adjective električni changes to match it:

• nominative: električni aparat
• dative: električnom aparatu

That is why you get električnom, not električni.

In English, you say belongs to with a preposition. In Serbian, the idea of to is often built into the case ending.

So instead of using a separate word for to, Serbian uses the dative case:

• pripada aparatu = belongs to the device

The ending -u in aparatu shows that relationship.

Yes. Kabl is the subject.

It is in the nominative singular, which is the basic subject form:

• kabl = cable

So the structure is:

• Kabl = the cable
• pripada = belongs
• električnom aparatu = to the electrical device

Because it is the subject, so it stays in the nominative case.

Many masculine nouns in Serbian have no extra ending in the nominative singular, so kabl appears in its basic form.

Compare:

• kabl = nominative
• kabla = genitive
• kablu = dative/locative

In this sentence, only aparat changes, because it is the noun governed by pripadati.

Yes. Serbian word order is more flexible than English because the case endings show the grammatical roles.

The most neutral order here is:

• Kabl pripada električnom aparatu.

But you could also change the order for emphasis, for example:

• Električnom aparatu pripada kabl.

That still means essentially the same thing, but the emphasis shifts. English usually cannot do this as freely.

Because Serbian normally does not use articles like the or a/an.

So:

• kabl can mean a cable or the cable
• električni aparat can mean an electrical device or the electrical device

The exact meaning depends on context.

You negate it by putting ne before the verb:

• Kabl ne pripada električnom aparatu.
• The cable does not belong to the electrical device.

This is the normal way to negate present-tense verbs in Serbian.

A very common way is to use Da li:

• Da li kabl pripada električnom aparatu?
• Does the cable belong to the electrical device?

In speech, intonation can also sometimes make it a question, but Da li is the clearest standard pattern for learners.

Kabl is a normal and very common Serbian word for cable.

You may also see kabel in some contexts, depending on region, style, or technical usage, but kabl is very standard and natural in everyday Serbian.