Greenhouse Management Online

During photosynthesis, light provides the energy required to fix (reduce) which atmospheric gas to form carbohydrates?
1. N2
2. O2
3. CO2
4. SO3
5. None of the above
Which is a term that refers to changes in plant growth and development that are controlled or influenced by light but not as a function of photosynthesis?
1. Thigmotrophic
2. Photomorphogenic
3. Skolotrophic
4. Alphatrophic
5. None of the above
Which is the term used to describe discrete particles of light with varying energy levels?
1. Photons
2. Volts
3. Mhos
4. Ohms
5. None of the above
To what does the term "PAR" refer?
1. Photon altered radiation
2. Photosynthetically active radiation
3. Photosynthetically altered radiation
4. Photonically absorbed radiation
5. None of the above
What range of wavelengths is generally used to define "PAR"?
1. 400 - 700 nm
2. 500 - 900 nm
3. 200 - 900 nm
4. 500 - 1000 nm
5. None of the above
Which term refers to the duration (over a 24 hour period) that a plant perceives light?
1. Skotoperiod
2. Nictoperiod
3. Optiperiod
4. Photoperiod
5. None of the above
A plant that becomes reproductive when the night length is less than some critical value is referred to as being what type of plant?
1. Long-day plant
2. Short-day plant
3. Day-neutral plant
4. Facultative plant
5. None of the above
A plant that becomes reproductive when the night length exceeds some critical value is referred to as being what type of plant?
1. Long-day plant
2. Short-day plant
3. Day-neutral plant
4. Facultative plant
5. None of the above
Why are footcandles not considered an appropriate measure of light with respect to photosynthesis?
1. The instrument used to measure footcandles are non longer available.
2. The measurement is expressed as Einsteins/second/square meter.
3. Devices to measure footcandles mimic the sensitivity of the human eye.
4. All of the above
5. None of the above
What are the units of measure for quantum flux density?
1. watts
2. moles/m(Square)/second
3. volts
4. watts/m(Square)
5. None of the above
What is the optimal light level (mmole/m(Square)/second) for production of geraniums (Pelargonium x hortorum)?
1. 150 - 250
2. 250 - 450
3. 600 - 900
4. 900 - 1200
5. None of the above
What is the optimal light level (mmole/m(Square)/second) for most foliage plants?
1. 150 - 250
2. 250 - 450
3. 600 - 900
4. 900 - 1200
5. None of the above
Which is not a common method used to reduce light levels in a greenhouse?
1. Latex shading
2. Polypropylene shade cloth
3. Aluminum-coated polyester shade cloth
4. Retractable shade systems
5. None of the above
Which are common plant responses to suboptimal light levels?
1. Flower bud abortion
2. Reduced growth rates
3. Increased internode lengths
4. Increased disease incidence
5. All of the above
Incandescent lamps are typically not used for photosynthetic lighting. This is because, in addition to the relatively low quantum flux density provided by a typical incandescent bulb, a large portion of the energy given off by an incandescent bulb is emitted as what type of radiation?
1. Infrared
2. Radio waves
3. X-rays
4. Blue visible light
5. None of the above
Which is (are) a significant difference(s) between "warm white" and "cool white" fluorescent lamps?
1. Warm whites emit more photons in the blue region of the visible spectrum
2. Warm whites emit more photons in the red region of the visible spectrum
3. Cool whites are only available 60-watt bulbs
4. Cool whites are only available in 100-watt bulbs
5. None of the above
Which is (are) a significant difference(s) between incandescent lamps and fluorescent lamps?
1. The type of ballast required
2. Efficiency rating
3. Bulb life span
4. Wavelengths emitted
5. All of the above
For what does the term "HID" stand with respect to greenhouse lighting?
1. Heavy industrial lighting
2. Heavy industrial density
3. High intensity discharge
4. High incandescent discharge
5. None of the above
What is a major reason that low-pressure sodium lamps are not well suited for use in HID lighting in greenhouses?
1. They emit light in a narrow band at approximately 590 nm
2. They emit light in a narrow band at approximately 680 nm
3. They emit light in a narrow band between 400 to 700 nm
4. They emit light in a narrow band at approximately 730 nm
5. None of the above
Which is the most common type of bulb used for HID lighting in greenhouses?
1. Low-pressure sodium
2. High-pressure sodium
3. Incandescent
4. Pressurized incandescent
5. Warm white fluorescent
When using incandescent bulbs to create a night interruption and an artificial "long day", what is the most common period during the night that the lights are turned on?
1. 5:00 to 7:00PM
2. 4:00 to 10:00PM
3. 10:00PM to 2:00AM
4. 5:00AM to 8:00AM
5. None of the above
When conducting HID lighting to increase photosynthesis, the lamps are turned on for approximately how long?
1. 3 hours
2. 4 hours
3. 16 hours
4. 24 hours
5. None of the above
Which type of bulb is most commonly used in greenhouse to conduct a night interruption and produce and artificial long day?
1. Warm white fluorescent
2. Cool white fluorescent
3. Incandescent
4. Low pressure sodium
5. None of the above
A shade cloth that blocks out light is often used to create which photoperiodic condition in a greenhouse?
1. A artificial short day
2. A artificial long day
3. A neutral day length
4. All of the above
5. None of the above
What is the function of a reflector used on an HID lamp?
1. Improve the distribution and uniformity of the emitted light
2. Deflect rain or water that might drip from the ceiling
3. Deflect heat generated by the ballast
4. Serve as a balance for the ballast
5. None of the above

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Unit 1

Lighting

Self-Test