Solar Radiation and Energy

The device used in traffic signal lights is Solar traffic light. are signalling devices powered by solar panels positioned at road intersections, pedestrian crossings and other locations to control the flows of traffic. 

Solar cells are made of semiconductor materials like silicon, gallium, or germanium. Platinum is a metal and is not a semiconductor, so it cannot be used to make a solar cell.

Solar cell use light energy from photons (basic unit of light energy) and convert it to electricity using semiconductor physics.

A solar cell converts light energy into electrical energy.

Photovoltaic cells, commonly known as solar cells, convert light energy directly into electricity. They utilize the photovoltaic effect to generate current when exposed to solar radiation.

Output of solar cell occurs at a constant voltage. Using a group of solar cells in the solar panel increases the amount of current produced. Also, as area is increased more solar energy is captured and more electrical energy is produced.

Solar cookers use concave or flat reflectors (mirrors) to concentrate sunlight onto a cooking vessel, maximizing the harvested solar energy.

When solar radiation enters the atmosphere, it is absorbed by the clouds and gases and heats the earth's surface. The earth, in return, reflects some of this heat into the atmosphere as infrared radiation. Most of this infrared radiation gets absorbed by atmospheric gases such as carbon dioxide, methane, nitrous oxide, and ozone, commonly known as greenhouse gases. These gases send the infrared radiation back to the earth's surface, thereby heating the surface again. This cycle repeats several times, thereby resulting in the greenhouse effect.

The gases in the troposphere of the atmosphere absorb the sun radiations and trap them so that they do not reflect back. This process allows the heat to remain trapped with in the atmosphere and the earth surface remains warm. This process is called greenhouse effect and the absorbed radiations striking the earth's surface are called green house flux. Carbon dioxide, water vapour, oxides of nitrogen are useful for this purpose. 

In an ecosystem, energy enters from the sun as solar energy and is converted into chemical energy by producers, but the primary source driving the entire flow is solar radiation.

Approximately 50 percent of the solar radiation reaching the outer atmosphere is absorbed or reflected by the atmosphere, clouds, and surface, while the rest reaches the Earth's surface.

Solar radiation reaching the Earth's atmosphere consists of various wavelengths. Approximately 10 percent of the total solar energy is in the ultraviolet range.

Naturally subsidized solar-powered ecosystems, such as estuaries or certain forests, receive additional energy inputs. The range of 10,000 to 40,000 kcal/m2 per year is a standard estimate for these types of systems.

The device which can trap the solar energy and convert the solar energy into an electrical form of energy is called as the solar cell. Solar cells are generally used for the storage of the radiations from the sun in the form of energy resource. These cells are used in the solar panels for the generation of electricity for the street lights. 

Solar energy can be harvested through various technologies, including photovoltaics (converting light to electricity), solar heating (thermal), and artificial photosynthesis (research-based chemical energy conversion).