Solar Energy Multiple Choice Questions on “Solar Distillation or Desalination of Water”.
1. What is solar distillation?
a) Use solar energy to evaporate water and collect its condensate within the same closed system
b) Use solar energy to evaporate water and collect it within the same closed system
c) Use solar energy to collect the condensate of water within the same closed system
d) Use solar energy to evaporate water and collect its condensate within different closed systems
Answer: a
Clarification: Solar distillation is the use solar energy to evaporate water and collect its condensate within the same closed system. It is important to note that the same system is used to both evaporate and condensate water.
2. Which of the following houses the process of solar distillation?
a) Solar thermo-mechanical system
b) Solar still
c) Photovoltaics
d) Heat engines
Answer: b
Clarification: Solar still houses the process of solar distillation. Solar thermo-mechanical system, photovoltaics and heat engines are not used to perform distillation.
3. Which of the following is a configuration of solar still?
a) Solar panel
b) Solar cell
c) Cone shaped
d) Frustum shaped
Answer: c
Clarification: The three basic configurations of solar still are cone shaped, box-like and frustum shaped. Solar cells and panels are not solar stills and are not used for solar distillation.
4. Which of the following best describes the process of solar distillation?
a) Influent → solar distillation system → salty solute remains → evaporation of volatile solvents as effluents
b) Influent → evaporation of volatile solvents as effluents → solar distillation system → salty solute remains
c) Influent → solar distillation system → evaporation of volatile solvents as effluents → salty solute remains
d) Solar distillation system → influent → evaporation of volatile solvents as effluents → salty solute remains
Answer: d
Clarification: The influent enters the solar distillation system. The volatile solvents evaporate as effluents leaving behind salty solute.
5. Which of the following is an example of solar distillation?
a) Natural water cycle
b) Fractional distillation
c) Reverse osmosis
d) Osmosis
Answer: a
Clarification: Natural water cycle is a very common example of solar distillation that the earth experiences. Fractional distillation, osmosis and reverse osmosis are not solar distillation.
6. What are the two categories of solar still?
a) Active and deactivate
b) Active and passive
c) Box and cone
d) Passive and pit
Answer: b
Clarification: Active and passive are the two main categories of solar still. Box, cone and pit are the basic configurations of solar still.
7. What do the two categories of solar still namely, active and passive depict?
a) The method of evaporation
b) The method of condensation
c) The method of acquiring energy to drive evaporation
d) The method of collecting evaporated water
Answer: c
Clarification: The two categories of solar still depict the method of acquiring energy to drive evaporation. Evaporation, condensation and collection of condensate are performed only after energy is supplied to the system.
8. What is an active solar still?
a) A solar still that solely relies on sun to distill water
b) A solar still that relies only on sun and wind
c) A solar sill that automatically gets activated when sun shines on it
d) A solar still that uses additional heat sources apart from sun
Answer: d
Clarification: An active solar still uses additional heat sources apart from sun. These additional heat sources are used to promote existing thermal processes like initial start-up.
9. Which of the following are examples of active solar stills?
a) Compound Parabolic Concentrators and flat plate collectors
b) Solar heater and photovoltaics
c) Flat plate collectors and heat engines
d) Compound parabolic concentrators and sun
Answer: a
Clarification: Compound parabolic concentrators, flat plate collectors and solar heaters are examples of active solar stills. Photovoltaics and heat engines are not solar stills. Sun is the energy source of solar still.
10. Active stills demote faster and larger quantities of freshwater generation.
a) True
b) False
Answer: b
Clarification: Active stills demote faster and larger quantities of freshwater generation. This comes at the cost of increased design complexity and manufacturing.
11. What is a passive solar still?
a) A solar still that uses photovoltaics to start
b) A solar still that relies only on sun and wind
c) A solar still that solely relies on sun to distill water
d) A solar still that uses additional heat sources apart from sun
Answer: c
Clarification: A passive solar still is a conventional solar still that solely relies on the sun to distill water. Though the process may be slow it generally has a lower design complexity as compared to an active solar still.
12. Which of the following is a type of passive stills?
a) Solar still with compound parabolic concentrator
b) Single-effect stills with flat plate collectors
c) Multi-effect stills with compound parabolic concentrator
d) Single-effect solar still
Answer: d
Clarification: Single-effect and multi-effect solar stills are types of passive stills. However, if any of these systems are attached with additional thermal sources like compound parabolic concentrators and flat plate collectors, they become active solar stills.
13. In a single-effect still, it is crucial to keep the distiller _______
a) airtight
b) aerated
c) connected with another distiller
d) connected with multiple distillers
Answer: a
Clarification: Single-effect stills are the simples and popularly used solar stills. In a single-effect solar still, it is a crucial design challenge to keep the distiller airtight. It uses a single interface to convey the energy and collect the condensate.
14. Neutral stills use seawater greenhouses to create freshwater.
a) False
b) True
Answer: b
Clarification: Neutral stills use seawater greenhouses to create freshwater. They are neutral because the energy that goes into creating freshwater is used to grow plants that promote evaporative cooling of air inside.
15. A good insulator is necessary to reduce thermal losses in solar stills.
a) True
b) False
Answer: a
Clarification: A good insulator is necessary to reduce thermal losses in solar stills. In fact, the insulators should be so good that they can prolong the evaporation to night.