PSS 10; light; test 2
Terms
undefined, object
copy deck
- What is the limiting factor for growing plants indoors?
- -light
- How can light be measured?
-
-footcandle
-lux - What is a footcandle?
- -the unit of illumication equivalent to that produced by a standard candle at a distance of 1 foot
- What is lux?
- -the unit of illumination equivalent to that produced by a standard candle at a distance of 1 meter
- What are some scientific light terms?
-
-candela
-lumen
-photon flux
-quanta
-joules - What can affect light penetration into a room?
-
-type (glass/plastic/glazing)
-reflection
-barriers
-orientation
-latitude
-geographic region - What color waves does chlorophyll often use?
- -blue and red
- What are the Pro's to incandescent bulbs?
-
-small
-no special fixtures
-dramatic
-range of wattages available - What are the Con's to incandescent bulbs?
-
-concentrated light
-only 7% usable energy in light
-90% of energy wasted on heat
-short life (750 hrs)
-high in red/orange, low blue - What are the Pros to fluorescent tubes?
-
-diffuse light
-efficient
-22% of energy usable light
-36% of energy wasted on heat
-long life (8,000-9,000 hrs) - What are the Con's to fluorescent tubes?
-
-work best if 70-90 degrees
-fixtures bulky
-low far-red emission
-light cannont be concentrated - What are the Pro's to sodium vapor lamps?
- -25-35% of energy visible light
- What are the Con's of sodium vapor lamps?
-
-yellow/orange/red spectral emission only
-large ballast (special fixtures) - What are some ways to increase artificial light?
-
-added white reflectors to fluorescent fixtures
-paint surrounding walls white
-clean tubes to remove dust
-change tubes regularly
-keep plants centered under fluorescent tubes - What is the minimum light required for plant maintainance?
- -100 fc
- How do you find the amount of total light needed per day?
- -footcandles of light x hours of light/day