1.
The average radiation intensity received per unit area perpendicular to earth surface at a mean sun-earth distance.
Correct Answer
C. Solar constant
Explanation
The term "solar constant" refers to the average radiation intensity received per unit area perpendicular to the Earth's surface at a mean sun-earth distance. It represents the amount of solar energy that reaches the Earth's atmosphere and is an important factor in understanding climate and weather patterns. The solar constant helps scientists measure and quantify the amount of energy that the Earth receives from the Sun, allowing for a better understanding of solar radiation and its effects on our planet.
2.
The value of solar constant is:
Correct Answer
A. 1367 W/ m2
Explanation
The solar constant is the amount of solar electromagnetic radiation received at the outer atmosphere of Earth. It represents the average solar power per unit area that is received perpendicular to the Sun's rays at a distance of one astronomical unit. The unit for power is watts (W) and the unit for area is square meters (m2), so the correct answer is 1367 W/m2.
3.
____________ is the instrument which is used to measure the direct radiation.
Correct Answer
C. Pyrheliometer
Explanation
A pyrheliometer is an instrument used to measure direct radiation. It is designed to measure the intensity of solar radiation received from the sun's direction. Unlike a sunshine recorder, which measures total sunlight duration, or a pyranometer, which measures total solar radiation, a pyrheliometer specifically measures direct solar radiation. Therefore, the correct answer is pyrheliometer.
4.
A Pyranometer is used to measure the ________________,
Correct Answer
A. Global radiation
Explanation
A pyranometer is a device used to measure global radiation, which refers to the total amount of solar radiation (both direct and diffuse) that reaches a particular surface. It is designed to measure the combined effect of direct sunlight and the scattered sunlight from the atmosphere. This measurement is important in various fields such as meteorology, solar energy studies, and climate research. The pyranometer is specifically calibrated to accurately measure the global radiation received by the surface it is placed on.
5.
Concentration factor of Flat plat collector is
Correct Answer
B. C=1
Explanation
The concentration factor of a flat plate collector refers to the ratio of the solar radiation incident on the collector surface to the solar radiation incident on a horizontal surface. A concentration factor of 1 means that the solar radiation incident on the collector surface is equal to the solar radiation incident on a horizontal surface. This implies that there is no concentration or focusing of solar radiation in the collector, and it operates at the same level as a horizontal surface.
6.
____________ collector which absorbs the both direct and diffuse radiation in that entire area.
Correct Answer
B. Non concentration
Explanation
A non-concentration collector is a type of solar collector that is designed to absorb both direct and diffuse radiation in a given area. Unlike concentrating collectors, which focus sunlight onto a smaller area to increase efficiency, non-concentration collectors are designed to capture sunlight from a larger area without focusing it. This allows them to absorb both direct sunlight and diffuse sunlight that is scattered by the atmosphere. By capturing a wider range of sunlight, non-concentration collectors can maximize their energy output and are suitable for applications where high efficiency is not the primary concern.
7.
Indicative temperature of evacuated tube collector is:
Correct Answer
A. 150 deg.cel.
Explanation
The indicative temperature of an evacuated tube collector is 150 degrees Celsius. This is the correct answer because an evacuated tube collector is designed to efficiently absorb and retain solar energy, allowing for higher temperatures to be reached. However, 150 degrees Celsius is a reasonable temperature that can be achieved without causing damage to the system or compromising its performance.
8.
Usually, the absorber plate of flat plate collector is made up of?
Correct Answer
D. Copper
Explanation
The absorber plate of a flat plate collector is typically made up of copper. Copper is a popular choice for the absorber plate because it has excellent thermal conductivity, allowing it to efficiently absorb and transfer heat from the sun to the fluid circulating through the collector. Copper is also durable, corrosion-resistant, and readily available, making it an ideal material for this application.
9.
In evacuated tube collector _________is used as an insulation material.
Correct Answer
C. Vacuum
Explanation
In evacuated tube collectors, vacuum is used as an insulation material. Vacuum is a state of low pressure where there is no air or any other material present. This lack of air molecules prevents heat transfer through conduction and convection, making vacuum an excellent insulator. By using vacuum as insulation in evacuated tube collectors, heat loss is minimized, allowing for more efficient collection and retention of solar energy.
10.
_______ is a box that the collector has enclosed in holds the components together, protect them from weather, facilitates installation of the collector on a roof or appropriate frame.
Correct Answer
A. Enclosure
Explanation
The correct answer is Enclosure. An enclosure is a box that the collector has enclosed in, which holds the components together, protects them from weather, and facilitates the installation of the collector on a roof or appropriate frame.
11.
In indiaFlat-plate collectors facing ___________ at fixed tilt___________.
Correct Answer
C. South, latitude +/_ 15 deg.
Explanation
Flat-plate collectors in India are most effective when they are facing south at a fixed tilt. This is because the sun is positioned in the southern part of the sky in the northern hemisphere, including India. By facing south, the collectors can receive maximum sunlight throughout the day, maximizing their efficiency in generating solar energy. The latitude range of +/- 15 degrees allows for some flexibility in the tilt angle, accommodating for variations in the specific location within India.
12.
Thermal conductivity of copper absorber plate is:
Correct Answer
B. 376 W/ m K
Explanation
The thermal conductivity of a material determines its ability to conduct heat. In this case, the correct answer is 376 W/m K, which stands for watts per meter Kelvin. This means that the copper absorber plate can conduct heat at a rate of 376 watts per meter for every degree Kelvin of temperature difference.
13.
In Flat plate collectors’ medium can achieve temperature range.
Correct Answer
A. 60-70 deg.cel
Explanation
Flat plate collectors are a type of solar thermal collector that are used to convert sunlight into heat energy. They consist of a flat plate that is exposed to the sun and a medium (usually water or a mixture of water and antifreeze) that flows through the plate to absorb the heat. The given answer of 60-70 deg.cel indicates that the medium in flat plate collectors can achieve temperatures in this range. This temperature range is suitable for many applications such as heating water for domestic use or space heating.
14.
Unit of the intensity of solar radiation.
Correct Answer
B. W/m2
Explanation
The unit of the intensity of solar radiation is expressed in W/m2, which stands for watts per square meter. This unit measures the amount of power per unit area that is received from the sun. It represents the rate at which solar energy is incident on a given surface area, indicating the amount of energy that can be harnessed or absorbed by that area.
15.
_________ is a component of collectors.
Correct Answer
B. Insulator
Explanation
An insulator is a component of collectors. It is a material or substance that does not conduct electricity, which makes it ideal for use in collectors to prevent the flow of electric current. By using an insulator, collectors can effectively isolate and protect the desired components or circuits from unwanted electrical connections or interference.