Я перевіряю графік відключень у телефоні.

Yes. Ukrainian often drops subject pronouns when the verb already makes the person clear.

Перевіряю already means I check / I am checking, so both of these are natural:

• Я перевіряю графік відключень у телефоні.
• Перевіряю графік відключень у телефоні.

Including я can add emphasis, contrast, or clarity.

Перевіряю is the 1st person singular present tense form of the imperfective verb перевіряти.

So it means:

• I check
• I am checking

Because it is imperfective, it can describe either:

• an action happening right now, or
• a repeated/habitual action

The perfective partner is перевірити. Its 1st person singular future form is перевірю = I will check.

Here графік is the direct object of перевіряю, so it is in the accusative case.

But графік is a masculine inanimate noun, and for masculine inanimate nouns, the accusative singular is usually the same as the nominative singular.

So:

• nominative: графік
• accusative: графік

That is why the word does not visibly change.

Because відключень is the genitive plural of відключення.

In Ukrainian, a noun like графік often takes another noun in the genitive to mean a schedule of ... or a timetable of ....

So:

• графік відключень = schedule of outages / disconnections

This is a very common pattern in Ukrainian.

Because the schedule normally contains multiple outages, not just one.

So графік відключень sounds natural when talking about planned power cuts or other repeated disconnections.

If you meant one specific outage, singular could be possible in some contexts, but in real life plural is much more natural here.

Телефоні is the locative singular form of телефон.

After у / в when they mean in or inside/on a device, Ukrainian often uses the locative case.

So:

• dictionary form: телефон
• locative: у телефоні / в телефоні

That is why the ending changes to -і.

Literally it is closer to in the phone, but in natural English the idea is usually on my phone.

In Ukrainian, у / в телефоні can mean that the information is being accessed on the phone device, for example in an app, message, note, or website.

So the sentence means something like:

• I’m checking the outage schedule on my phone.

Yes. У and в are often interchangeable, and the choice is frequently made for euphony—whichever sounds smoother next to the surrounding words.

So both are possible:

• Я перевіряю графік відключень у телефоні.
• Я перевіряю графік відключень в телефоні.

You will hear both. Learners should get used to this у / в alternation in Ukrainian.

Usually not if you mean using my phone to look something up.

• у / в телефоні = in/on the phone device, inside it
• по телефону = by phone, over the phone, using a call
• на телефоні can have other meanings and usually is not the best choice here

So for this sentence, у телефоні / в телефоні is the best fit.

No. Ukrainian word order is fairly flexible.

The version given is natural and neutral:

• Я перевіряю графік відключень у телефоні.

But other orders are possible if you want to emphasize something:

• Графік відключень я перевіряю у телефоні.
  Emphasis on the outage schedule
• У телефоні я перевіряю графік відключень.
  Emphasis on where I am checking it

So the word order can change, but the original sentence is a good default.

Перевіряю means I check / I’m checking, so it suggests consulting something to confirm information.

Дивлюся means I look / I’m looking, which focuses more on the act of looking.

So:

• перевіряю графік = I check the schedule
• дивлюся графік = I look at the schedule

Both can work in some contexts, but перевіряю is especially good if the idea is checking for information.