Energy and Light Flashcards
PAR light refers to electromagnetic energy with wave lengths from 380 - 750 nm. TRUE OR FALSE.
FALSE.
400nm-700nm.
A greenhouse with sidewall vents is an example of a closed thermo-dynamic system. TRUE OR FALSE.
False. (*)
Clarity is a glazing specification that…
indicates the percentage of the total amount of light transmitted through the material that is direct transmission
The percentage of electromagnetic energy that is transmitted or reflected by an object is dependent on…
-the type of material its made from
-the angle of incidence of the incoming rays
Thermal conductivity refers to the rate at which heat energy can be transferred through a material for every degree difference in temperature from one side to the other. TRUE OR FALSE.
True (*)
Please select all that apply. The two main types of energy that we are concerned with in greenhouse management are…
-thermal energy
-electromagnetic energy
The sun produces a spectrum of electromagnetic energy only in the UV and Visible Light wavelengths.
False. (*)
Plants grown under UV-A and UV-B light tend to…
-have shortened stems with thicker leaves and cuticles to protect against the high energy light
Electromagnetic energy is sometimes referred to as radiation.
True
Two types of Infrared radiation that are important to greenhouse management are Near Infrared and Far Infrared radiation.
True
Coatings that are added to a glazing material to change its properties can be sprayed on after the greenhouse is constructed.
TRUE OR FALSE.
True
The second law of thermodynamics states that…
heat will transfer from objects or areas of high temperature to low temperature.
It is always best to have glazing coatings and additives permanently manufactured into the product at the time of ordering.
TRUE OR FALSE
False
UV-C light is beneficial to plant growth.
TRUE OR FALSE
False.
Heat energy can be transferred by…
-conduction, convention and radiation
The type of heat energy that is associated with a change of phase (ie solid <-> liquid <-> gas) is called…
latent heat
When we study the transfers of all the light and heat energy between the internal and external greenhouse environments, we are studying the…
Haze is a glazing specification that…
indicates the percentage of the total amount of light transmitted through the material that is diffuse
Photosynthetically active radiation refers to the wavelengths of light that are primarily absorbed by chlorophyll. TRUE OR FALSE
True
Light Transmission % is a glazing specification that…
Please select all that apply. Which of the following features are characteristic of a proportional injector.
Please select all that apply. Which of the following features are characteristic of a peristaltic dosing pump.
A glazing material’s U-value…
