ضوء الطوارئ هنا.

Because Arabic often uses a nominal sentence in the present tense, with no word for is/are.

So ضوء الطوارئ هنا literally looks like:

• ضوء الطوارئ = the emergency light
• هنا = here

And the full meaning is The emergency light is here.

In English, you must say is, but in Arabic present-tense sentences like this, it is normally omitted.

This is because ضوء الطوارئ is an iḍāfa construction, often called a genitive construction or noun + noun construction.

In an iḍāfa:

• the first noun usually does not take الـ
• the second noun determines whether the whole phrase is definite or indefinite

Here:

• ضوء = light
• الطوارئ = the emergencies / emergency-related matters

So ضوء الطوارئ means literally light of the emergency/emergencies, which in natural English becomes the emergency light.

Because الطوارئ is definite, the whole phrase is definite.

It is an iḍāfa phrase:

• ضوء = the first term of the iḍāfa
• الطوارئ = the second term of the iḍāfa

The relationship is similar to:

• باب البيت = the door of the house
• مدير المدرسة = the principal of the school
• ضوء الطوارئ = the emergency light

In English, this often becomes either:

• the light of the emergency
• the emergency light

The second version is the more natural English translation.

That is a very common question. طوارئ is a plural form in Arabic, but it is often used in fixed expressions that English translates with a singular adjective-like word such as emergency.

So in real usage:

• قسم الطوارئ = emergency department
• حالة طوارئ = state of emergency
• ضوء الطوارئ = emergency light

You do not need to force the English to sound plural. This is just how Arabic expresses the idea.

Yes. In this sentence, هنا functions as the part that tells you something about ضوء الطوارئ.

Very roughly:

• ضوء الطوارئ = the topic / subject
• هنا = the comment / predicate

So the structure is:

• The emergency light
  • is here

In traditional grammar, هنا is an adverb of place, but in the sentence it serves as the predicate meaning is here.

A fully vowelled version would be:

ضَوْءُ الطَّوَارِئِ هُنَا

A helpful pronunciation guide:

• ضَوْءُ = ḍawʾu
• الطَّوَارِئِ = aṭ-ṭawāriʾi
• هُنَا = hunā

A few things to notice:

• الـ in الطوارئ assimilates to ط, so it is pronounced aṭ-, not al-
• the final sound in ضوء includes a hamza: ḍawʾ
• هنا is pronounced hunā

In full case-marked MSA, it would normally be:

ضوءُ الطوارئِ هنا

More fully vowelled:

ضَوْءُ الطَّوَارِئِ هُنَا

Why?

• ضوءُ is nominative because it is the subject/topic of the nominal sentence
• الطوارئِ is genitive because it is the second noun in an iḍāfa
• هنا is indeclinable, so it does not change its ending

In normal speech, news headlines, and many written contexts, these case endings are often not pronounced.

Yes, you can, but the emphasis changes.

• ضوء الطوارئ هنا = The emergency light is here
• هنا ضوء الطوارئ = Here is the emergency light / The emergency light is here

Putting هنا first gives more focus to the location, similar to English Here is...

Both are understandable, but the original sentence presents the emergency light as the topic first.

It can be understood that way in some contexts, but that is not the most direct reading.

The sentence as written most naturally means:

The emergency light is here.

If you specifically wanted There is an emergency light here, Arabic would more commonly use something like:

يوجد ضوء طوارئ هنا

That said, short signs and labels can be flexible, so context matters.

Because Arabic often uses a noun + noun construction where English uses an adjective.

English says:

• emergency light
• school principal
• car door

Arabic often says:

• ضوء الطوارئ = light of emergency / emergency light
• مدير المدرسة = director of the school / school principal
• باب السيارة = door of the car / car door

So even though emergency feels adjective-like in English, Arabic expresses it here with a noun inside an iḍāfa construction.

Yes. ضوء commonly means light in the sense of illumination.

Depending on context, Arabic can also use words like:

• نور = light, brightness
• مصباح = lamp, light fixture

But ضوء الطوارئ is a natural way to say emergency light.

If you said مصباح الطوارئ, that would sound more like emergency lamp or emergency light fixture, while ضوء الطوارئ focuses more on the light itself or the designated emergency light.

Three things:

First, ض is an emphatic consonant. It is not the same as plain d. In careful transliteration, it is written ḍ.

Second, ضوء contains a hamza at the end of the syllable:

• ضَوْء
• roughly ḍawʾ

That little break before the ending matters.

Third, when read in full grammar, it may be ضوءُ with a final -u ending, but in pause people often stop on ضوء without clearly pronouncing the case ending.

Yes. هذا ضوء الطوارئ means This is the emergency light.

That is slightly different from ضوء الطوارئ هنا:

• هذا ضوء الطوارئ = identifying something
• ضوء الطوارئ هنا = stating its location

So if you are pointing at a specific object, هذا ضوء الطوارئ is natural. If you are saying where it is, ضوء الطوارئ هنا is the better choice.