Led Grow Light Key Features 4

Question 1

The Daily Light Integral (DLI) represents what?

Accepted Answer

Total moles of PAR light delivered per square meter per day

Answer

Peak wattage drawn at noon

Answer

The fixture's lifespan in days

Answer

Color accuracy over 24 hours

Question 2

If a fixture has high PPF but a wide beam angle, what is the likely effect on PPFD?

Accepted Answer

Lower PPFD at any single point due to spread

Answer

Higher PPFD at the center

Answer

No effect on PPFD

Answer

It increases efficacy

Question 3

Raising a grow light farther from the canopy generally does what?

Accepted Answer

Decreases PPFD but widens coverage

Answer

Increases PPFD and narrows coverage

Answer

Has no measurable effect

Answer

Raises efficacy in μmol/J

Question 4

Why is photon efficacy (μmol/J) a better comparison metric than wattage alone?

Accepted Answer

It accounts for usable light produced per energy unit

Answer

It measures heat output only

Answer

It reflects the fixture's price

Answer

It equals the lumen rating

Question 5

Which spectrum bias is typically emphasized during the seedling/vegetative stage?

Accepted Answer

More blue light to encourage compact, leafy growth

Answer

More far-red to force flowering

Answer

Pure green light

Answer

UV-C for sterilization

Question 6

A driver with a high power factor (e.g., 0.95) primarily benefits the grower by doing what?

Accepted Answer

Using electricity more efficiently from the grid

Answer

Increasing PAR output

Answer

Changing the color temperature

Answer

Extending the beam angle

Question 7

What does L70 rating on an LED grow light describe?

Accepted Answer

Hours until output drops to 70% of initial

Answer

Brightness at 70 watts

Answer

70% blue spectrum content

Answer

A 70-degree beam angle