Led Grow Light Key Features 2 — Questions and Answers
Question 1: What unit measures the total amount of photosynthetically active light a fixture delivers per second?
- PPF (μmol/s) (Correct answer)
- Lumens
- Lux
- Watts
Correct answer: PPF (μmol/s)
PPF (Photosynthetic Photon Flux) is measured in micromoles per second and reflects total usable light output for plants.
Question 2: Which metric tells you how much PAR light reaches a specific point on the canopy?
- PPFD (μmol/m²/s) (Correct answer)
- PPF
- CRI
- Color temperature
Correct answer: PPFD (μmol/m²/s)
PPFD measures photon density at a surface, indicating intensity at the canopy.
Question 3: A grow light's efficiency is best described by which spec?
- Efficacy in μmol/J (Correct answer)
- Total wattage
- Lumens per watt
- Beam angle
Correct answer: Efficacy in μmol/J
Photon efficacy (μmol/J) shows how many usable photons are produced per joule of energy.
Question 4: Which wavelength range is most associated with driving vegetative and flowering photosynthesis in PAR?
- 400–700 nm (Correct answer)
- 315–400 nm
- 700–800 nm
- 200–280 nm
Correct answer: 400–700 nm
PAR spans 400–700 nm, the band plants use most for photosynthesis.
Question 5: What feature lets a grower change a fixture's brightness over the grow cycle?
- Dimming control (Correct answer)
- Heat sink size
- IP rating
- Mounting bracket
Correct answer: Dimming control
A dimmer adjusts output to match seedling, veg, and flower light needs.
Question 6: A 'full-spectrum' LED grow light primarily aims to mimic what?
- Natural sunlight (Correct answer)
- Moonlight
- Incandescent bulbs
- Ultraviolet sterilizers
Correct answer: Natural sunlight
Full-spectrum LEDs reproduce a broad sunlight-like spectrum for balanced growth.
Question 7: Which spec indicates how a fixture's light intensity spreads across the grow area?
- Light footprint / coverage area (Correct answer)
- Color rendering index
- Power factor
- Surge rating
Correct answer: Light footprint / coverage area
The light footprint shows the effective canopy area a fixture can cover at a given height.
Led Grow Light Key Features 2
What unit measures the total amount of photosynthetically active light a fixture delivers per second?