die
Lichtstärke
💡 What Exactly is 'die Lichtstärke'?
Die Lichtstärke is a physical quantity that indicates how much light a light source (eine Lichtquelle) emits in a specific direction (Richtung). It's one of the seven SI base units and is measured in Candela (cd).
Basically, it describes the subjectively perceived brightness (subjektiv empfundene Helligkeit) of a point-like light source from a particular perspective.
You'll often encounter the term in:
- Physics & Optics: For describing lamps (Lampen), LEDs, stars (Sterne), etc.
- Photography & Film: Indirectly relevant when choosing lenses (although photographers often incorrectly refer to 'Lichtstärke' meaning the maximum aperture (maximale Blendenöffnung), which is technically the relative aperture (relative Öffnung)).
- Technology: In the specifications of lighting elements (Leuchtmitteln) and displays.
⚠️ It's important not to confuse Lichtstärke (luminous intensity) with Beleuchtungsstärke (illuminance, measured in Lux) or Lichtstrom (luminous flux, measured in Lumen).
Article rules for der, die, and das
-e/-ee → almost always feminine.
There are many -e nouns, many of which are feminine, but there are also some important exceptions.
Wisdom, power, rules → mostly feminine.
📐 Grammar of 'die Lichtstärke' in Detail
The word "Lichtstärke" is a feminine noun. Therefore, the article is always "die".
Declension Singular
| Case | Article | Noun |
|---|---|---|
| Nominative | die | Lichtstärke |
| Genitive | der | Lichtstärke |
| Dative | der | Lichtstärke |
| Accusative | die | Lichtstärke |
Declension Plural
The plural form "die Lichtstärken" is rarely used, mostly when comparing the luminous intensities of different sources.
| Case | Article | Noun |
|---|---|---|
| Nominative | die | Lichtstärken |
| Genitive | der | Lichtstärken |
| Dative | den | Lichtstärken |
| Accusative | die | Lichtstärken |
Example Sentences
- Die Lichtstärke dieser LED beträgt 15 Candela.
(The luminous intensity of this LED is 15 Candela.) - Wir müssen die Lichtstärke des Scheinwerfers messen.
(We need to measure the luminous intensity of the spotlight.) - Dank der hohen Lichtstärke ist die Lampe sehr effizient.
(Thanks to its high luminous intensity, the lamp is very efficient.) - Der Physiker erklärte den Unterschied zwischen Lichtstrom und Lichtstärke.
(The physicist explained the difference between luminous flux and luminous intensity.)
🗣️ How to Use 'Lichtstärke'?
The term "Lichtstärke" is primarily used in technical (technischen) and physical (physikalischen) contexts.
- Technology/Physics: Here, it refers to the precise meaning as a measure of luminous flux per solid angle (Lichtstrom pro Raumwinkel) (Unit: Candela). Example: "Die technischen Daten geben eine Lichtstärke von 50 cd an." (The technical specifications indicate a luminous intensity of 50 cd.)
- Photography: Photographers often talk about the "Lichtstärke" of a lens, but usually mean the maximum aperture (größtmögliche Blendenöffnung) (e.g., f/1.8). This isn't technically accurate but is common usage. A larger aperture lets more light onto the sensor, which is advantageous in low light. Example: "Dieses Objektiv hat eine beeindruckende Lichtstärke." (This lens has an impressive 'light strength' [referring to its large maximum aperture].)
- Everyday Language: In daily conversation, people are more likely to use "Helligkeit" (brightness) when referring to general luminosity. "Lichtstärke" sounds more specific and technical.
Comparison:
- Lichtstärke (cd): Intensity in one direction.
- Lichtstrom (lm): Total amount of light emitted by a source.
- Beleuchtungsstärke (lx): Amount of light arriving on a surface.
🧠 Mnemonics for Lichtstärke
Article Mnemonic: Words ending in "-stärke" (like Windstärke - wind strength, Sehstärke - visual acuity) are almost always feminine in German. So: die Stärke -> die Lichtstärke.
Meaning Mnemonic: Think of a strong light source (starkes Licht). The Stärke (strength/intensity) of the Licht (light) in one direction is the Lichtstärke.
🔄 Synonyms & Antonyms
Synonyms (Similar Meaning):
- Leuchtkraft (luminosity; often used synonymously, but can have other meanings)
- Helligkeit (brightness; colloquial, less precise than Lichtstärke)
- Intensität (intensity; general term, can refer to light)
Antonyms (Opposites):
- Dunkelheit (darkness; general opposite of light)
- There isn't a direct physical antonym for the quantity 'Lichtstärke'. One usually speaks of low or high luminous intensity (geringe oder hohe Lichtstärke).
Similar, but Different Terms:
- Lichtstrom (Lumen): Measures the total light output of a source in all directions (luminous flux).
- Beleuchtungsstärke (Lux): Measures how much light arrives on a specific surface (illuminance).
- Leuchtdichte (Candela per square meter): Measures the brightness of a surface from a specific direction (luminance).
😄 A Bright Joke
Fragt der Lehrer: "Was ist der Unterschied zwischen Lichtstrom und Lichtstärke?"
Antwortet Fritzchen: "Beim Lichtstrom bezahlt man für das ganze Licht, bei der Lichtstärke nur für die Richtung, in die es scheint!"
Translation:
The teacher asks: "What's the difference between luminous flux (Lichtstrom) and luminous intensity (Lichtstärke)?"
Little Fritz answers: "With luminous flux, you pay for all the light; with luminous intensity, you only pay for the direction it shines in!"
📜 Poem about Luminous Intensity
Die Kerze brennt, ein stilles Licht,
ihre Stärke zeigt sich im Gesicht
der Wand, die sie erhellt so klar,
in Candela messbar, wunderbar.
Die Lichtstärke, ein Strahl so rein,
dringt tief ins Dunkel hinein.
Translation:
The candle burns, a silent light,
its strength shows on the face
of the wall it illuminates so clear,
in Candela measurable, wonderful.
The luminous intensity, a beam so pure,
penetrates deep into the darkness.
❓ Riddle
Ich messe, wie hell 'was strahlt in eine Richtung nur,
bin eine Basisgröße der Physik-Natur.
Mein Name klingt nach Kraft und hellem Schein,
in Candela gibt man mich an, mal groß, mal klein.
Was bin ich?
Translation:
I measure how bright something shines in just one direction,
I am a base quantity in physics' nature.
My name sounds like strength and bright gleam,
In Candela I am stated, sometimes large, sometimes lean.
What am I? (Solution: die Lichtstärke / luminous intensity)
🧩 Other Information
Word Composition
The word "Lichtstärke" is a compound noun (Kompositum), composed of:
- Das Licht: (The light) Refers to electromagnetic radiation visible to the human eye.
- Die Stärke: (The strength/intensity) Means intensity or power here.
Together, the meaning is "intensity of light".
Unit
The SI unit for luminous intensity (Lichtstärke) is the Candela (cd). The name derives from the Latin word for candle, as historically the brightness of a standard candle served as a reference.
📝 Summary: is it der, die or das Lichtstärke?
The noun "Lichtstärke" is feminine. The correct article is always die: die Lichtstärke.