אני לא יודעת האם אור אולטרה-סגול מראה את הסמל.

יודעת is the feminine singular present-tense form of לדעת (to know).

So:

• אני לא יודעת = I (female speaker) don’t know
• אני לא יודע = I (male speaker) don’t know

Hebrew present-tense verbs usually agree with the subject in gender and number, even with אני.

Here האם means whether.

It introduces an indirect yes/no question:

• אני לא יודעת האם... = I don’t know whether...

This is different from a normal wh- question like what, where, why, etc. The speaker is unsure if something is true or not, so Hebrew uses האם.

In everyday spoken Hebrew, many people would say אם instead:

• אני לא יודעת אם אור אולטרה-סגול מראה את הסמל.

That is usually more conversational. האם sounds more formal or careful.

Yes, very often.

In this sentence:

• האם = more formal / standard
• אם = very common in speech

So both of these work:

• אני לא יודעת האם אור אולטרה-סגול מראה את הסמל.
• אני לא יודעת אם אור אולטרה-סגול מראה את הסמל.

For a learner, it is good to recognize both. If you want to sound natural in conversation, אם is very common.

Because מראה means shows / reveals / makes visible, while רואה means sees.

These come from related but different verbs:

• לראות = to see
• להראות = to show

So:

• אור אולטרה-סגול רואה את הסמל would mean Ultraviolet light sees the symbol, which makes no sense.
• אור אולטרה-סגול מראה את הסמל means Ultraviolet light shows/reveals the symbol.

This is a very common point of confusion because the verbs are similar in form.

את is the direct object marker. It appears before a definite direct object.

Here:

• הסמל = the symbol
• because it is definite (the symbol), Hebrew uses את

So:

• מראה את הסמל = shows the symbol

Important: את usually is not translated into English. It is a grammatical marker, not a separate word with meaning like with or to in this sentence.

Compare:

• מראה סמל = shows a symbol
• מראה את הסמל = shows the symbol

Because הסמל is definite (the symbol), while אור אולטרה-סגול is being used more generally here (ultraviolet light, not necessarily the ultraviolet light).

So:

• הסמל = the symbol
• אור אולטרה-סגול = ultraviolet light

If you wanted to say the ultraviolet light, you would normally make the noun phrase definite:

• האור האולטרה-סגול

Hebrew adjectives usually match definiteness too, so if the noun is definite, the adjective is typically definite as well.

Because in Hebrew, adjectives usually come after the noun.

So:

• אור = light
• אולטרה-סגול = ultraviolet

Together:

• אור אולטרה-סגול = ultraviolet light

This is normal Hebrew word order:

• noun + adjective

Just like:

• בית גדול = big house
• ספר מעניין = interesting book

not the English order adjective + noun.

Yes. מראה is the masculine singular present-tense form, and it agrees with אור, which is masculine singular.

So the structure is:

• אור = masculine singular subject
• מראה = masculine singular verb form in the present

If the subject were feminine singular, the form would change:

• המנורה מראה... = The lamp shows...
  (Here מנורה is feminine, so the verb would be מראה? Actually in present tense some forms can look the same in writing for masculine singular and feminine singular in certain verbs? For להראות, the present forms are:
  • masc. sg. מראה
  • fem. sg. מראה So in this particular verb, masculine and feminine singular look the same.)

That means in this sentence, agreement matters mainly in number, and the form happens to fit the singular subject naturally.

Yes, it functions as an adjective here.

In this sentence:

• אור אולטרה-סגול = ultraviolet light

And yes, it can change for gender and number, because the adjective part סגול behaves like a normal adjective:

• masculine singular: אולטרה-סגול
• feminine singular: אולטרה-סגולה
• masculine plural: אולטרה-סגולים
• feminine plural: אולטרה-סגולות

For example:

• קרינה אולטרה-סגולה = ultraviolet radiation
  (קרינה is feminine)
• קרניים אולטרה-סגולות = ultraviolet rays
  (קרניים is feminine plural)

Yes. In context, מראה can mean:

• shows
• reveals
• makes visible

With something like ultraviolet light, English often uses reveals or makes visible, even if the Hebrew uses the ordinary verb מראה.

So the Hebrew is normal, but the most natural English translation may depend on context.

A simple pronunciation guide would be:

Ani lo yoda'at ha'im or ultra-sagol mar'eh et ha-semel.

Roughly:

• אני = ah-NEE
• לא = loh
• יודעת = yo-DA-at
• האם = ha-IM
• אור = or
• אולטרה-סגול = OOL-tra sa-GOL
• מראה = mar-EH
• את = et
• הסמל = ha-SE-mel

Depending on accent and speaking style, pronunciations can vary a bit.

Yes, it is grammatical and understandable.

That said, many speakers in everyday Hebrew would more naturally say:

• אני לא יודעת אם אור אולטרה-סגול מראה את הסמל.

using אם instead of האם.

Also, depending on context, someone might choose a verb like מגלה (reveals) or חושף (exposes/reveals) if they want to emphasize that the light makes something hidden visible. But מראה is still perfectly normal and clear.