क्या आपको उस आदमी का नाम याद है?

At the start of this sentence, क्या is a yes/no question marker. It does not mean what here.

So:

• क्या आपको उस आदमी का नाम याद है? = Do you remember that man's name?

In other contexts, क्या can mean what, but sentence position matters a lot:

• क्या हुआ? = What happened?
• क्या आपको... याद है? = Do you... remember?

In everyday speech, Hindi can also ask this without क्या, just by using question intonation:

• आपको उस आदमी का नाम याद है?

That is also natural.

Because Hindi uses the expression याद होना in a different way from English to remember.

A very literal way to understand it is:

• आपको ... याद है = To you ... is remembered

So the person who remembers is often marked with को.

Examples:

• मुझे याद है = I remember
• तुम्हें याद है = you remember
• उसे याद है = he/she remembers
• आपको याद है = you remember (polite)

So आपको is not random; it is the normal pattern with याद है.

Yes. आप is the polite/formal word for you.

So this sentence sounds polite or respectful:

• क्या आपको उस आदमी का नाम याद है?

Less formal versions would be:

• क्या तुम्हें उस आदमी का नाम याद है? = informal/neutral you
• क्या तुझे उस आदमी का नाम याद है? = very informal/intimate

A learner should notice that only the pronoun changes here; the rest of the sentence stays basically the same.

Because उस is the oblique form of वह.

Hindi pronouns and demonstratives often have two forms:

• वह = direct form
• उस = oblique form

You use the oblique form when the word is followed by a postposition or is part of a phrase that takes one. Here, आदमी is followed by का, so the whole phrase is oblique:

• उस आदमी का नाम = that man's name

Compare:

• वह आदमी अच्छा है। = That man is good.
• उस आदमी का नाम... = that man's name...
• उस आदमी को... = to that man
• उस आदमी से... = from/with that man

A useful thing to notice: आदमी itself does not visibly change here, so the change is most obvious in वह → उस.

उस आदमी का नाम means the name of that man or that man's name.

Here:

• उस आदमी = that man
• का = possessive marker, like of or 's
• नाम = name

So the structure is:

• [that man] + [of] + [name]

Why का?

Because का / की / के agrees with the thing being possessed, not the possessor.
Here, the possessed thing is नाम, which is masculine singular, so you use का.

Compare:

• उस आदमी का नाम = that man's name (नाम is masculine singular)
• उस आदमी की बेटी = that man's daughter (बेटी is feminine)
• उस आदमी के बच्चे = that man's children (बच्चे is plural)

That’s because Hindi often expresses this idea differently from English.

English says:

• Do you remember the name?

Hindi often says something closer to:

• Is the name remembered to you?

So:

• याद = remembered / in memory
• है = is

Together, याद है means is remembered or more naturally remember.

Very common patterns are:

• मुझे याद है = I remember
• मुझे नहीं याद है = I don’t remember
• क्या तुम्हें याद है? = Do you remember?

This is one of those places where it is better to learn the whole pattern, not translate word by word too rigidly.

Because the thing being remembered here is नाम, which is singular.

In this kind of structure, the verb often agrees with the thing remembered, not with the person marked by को.

So:

• आपको उसका नाम याद है। = You remember his name.
  (नाम = singular, so है)

But:

• आपको उसके नाम याद हैं। = You remember his names.
  (नाम = plural in meaning here, so हैं)

Also:

• मुझे वे बातें याद हैं। = I remember those things/those matters.

So the verb changes according to what is remembered.

Hindi word order is flexible, but this version is very normal and clear:

• क्या आपको उस आदमी का नाम याद है?

You may also hear:

• आपको उस आदमी का नाम याद है?
  Same meaning, asked with rising intonation.

In conversation, some speakers may place क्या later:

• आपको उस आदमी का नाम याद है क्या?

That is more colloquial in many varieties of Hindi.

So the given sentence is a standard, safe form for learners.

In this sentence, आदमी clearly means man.

But in Hindi, आदमी can sometimes also mean person or human being, depending on context.

Examples:

• वह आदमी कौन है? = Who is that man?
• हर आदमी को सम्मान चाहिए। = Every person needs respect.

So its meaning can be narrow (man) or broader (person), but here उस आदमी most naturally means that man.

You usually put नहीं before याद:

• क्या आपको उस आदमी का नाम याद नहीं है? = Don’t you remember that man’s name?
• मुझे उस आदमी का नाम याद नहीं है। = I don’t remember that man’s name.

In everyday speech, people often shorten नहीं है to just:

• मुझे उस आदमी का नाम याद नहीं।

That is very common in conversation.