SSC CGL – SSC CGL Test 30

Read the following passage carefully and answer the questions given below it.<br><br> Every year, the sun irradiates the land masses on earth with the equivalent of 19,000 billion tons of oil equivalent (toe). Only a fraction - 9 billion toe - would satisfy the world's current energy requirements. Put differently, in 20 minutes, the amount of solar energy falling on the earth could power the planet for one year. Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year. Solar energy is the technology used to harness the sun's energy and make it useable. Today, the technology produces less than one tenth of one percent of global energy demand. All energy originates with the sun except for nuclear, geothermal and tidal energy. Solar energy comes to us as high intensity radiation (light energy). As it falls on the earth, it is transformed into heat by any surface or material - be it the atmosphere, soil, buildings, or even the furniture in front of a window. This heat also drives the world's weather systems including wind, rain and river flow. <br><br> Through photosynthesis, plants also turn solar energy into new growth. Many people are familiar with so­ called photovoltaic cells, or solar panels, found on things like spacecraft, rooftops, and handheld calculators. The cells are made of semiconductor materials like those found in computer chips. When sunlight hits the cells, it knocks electrons loose from their atoms. As the electrons flow through the cell, they generate electricity. Photo­voltaic were initially, and still are, used to power small and medium­sized applications, from the calculator powered by a single solar cell to off­grid homes powered by a photovoltaic array. They are an important and relatively inexpensive source of electrical energy where grid power is inconvenient, unreasonably expensive to connect, or simply unavailable. However, as the cost of solar electricity is falling, solar power is also increasingly being used even in grid­connected situations as a way to feed low­carbon energy into the grid. On a much larger scale, solar thermal power plants employ various techniques to concentrate the sun's energy as a heat source. The heat is then used to boil water to drive a steam turbine that generates electricity in much the same fashion as coal and nuclear power plants, supplying electricity for thousands of people. In one technique, long troughs of Ushaped mirrors focus sunlight on a pipe of oil that runs through the middle. The hot oil then boils water for electricity generation. Another technique uses movable mirrors to focus the sun's rays on a collector tower, where a receiver sits. Molten salt flowing through the receiver is heated to run a generator. Other solar technologies are passive. For example, big windows placed on the sunny side of a building allow sunlight to heat­ absorbent materials on the floor and walls. These surfaces then release the heat at night to keep the building warm. Similarly, absorbent plates on a roof can heat liquid in tubes that supply a house with hot water. Solar energy is lauded as an inexhaustible fuel source that is pollution and often noise free. The technology is also versatile. For example, solar cells generate energy for far­out places like satellites in Earth orbit and cabins deep in the Rocky Mountains as easily as they can power downtown buildings and futuristic cars. But solar energy doesn't work at night without a storage device such as a battery, and cloudy weather can make the technology unreliable during the day.

Solar panel is also known as­

Read the following passage carefully and answer the questions given below it.<br><br> Every year, the sun irradiates the land masses on earth with the equivalent of 19,000 billion tons of oil equivalent (toe). Only a fraction - 9 billion toe - would satisfy the world's current energy requirements. Put differently, in 20 minutes, the amount of solar energy falling on the earth could power the planet for one year. Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year. Solar energy is the technology used to harness the sun's energy and make it useable. Today, the technology produces less than one tenth of one percent of global energy demand. All energy originates with the sun except for nuclear, geothermal and tidal energy. Solar energy comes to us as high intensity radiation (light energy). As it falls on the earth, it is transformed into heat by any surface or material - be it the atmosphere, soil, buildings, or even the furniture in front of a window. This heat also drives the world's weather systems including wind, rain and river flow. <br><br> Through photosynthesis, plants also turn solar energy into new growth. Many people are familiar with so­ called photovoltaic cells, or solar panels, found on things like spacecraft, rooftops, and handheld calculators. The cells are made of semiconductor materials like those found in computer chips. When sunlight hits the cells, it knocks electrons loose from their atoms. As the electrons flow through the cell, they generate electricity. Photo­voltaic were initially, and still are, used to power small and medium­sized applications, from the calculator powered by a single solar cell to off­grid homes powered by a photovoltaic array. They are an important and relatively inexpensive source of electrical energy where grid power is inconvenient, unreasonably expensive to connect, or simply unavailable. However, as the cost of solar electricity is falling, solar power is also increasingly being used even in grid­connected situations as a way to feed low­carbon energy into the grid. On a much larger scale, solar thermal power plants employ various techniques to concentrate the sun's energy as a heat source. The heat is then used to boil water to drive a steam turbine that generates electricity in much the same fashion as coal and nuclear power plants, supplying electricity for thousands of people. In one technique, long troughs of Ushaped mirrors focus sunlight on a pipe of oil that runs through the middle. The hot oil then boils water for electricity generation. Another technique uses movable mirrors to focus the sun's rays on a collector tower, where a receiver sits. Molten salt flowing through the receiver is heated to run a generator. Other solar technologies are passive. For example, big windows placed on the sunny side of a building allow sunlight to heat­ absorbent materials on the floor and walls. These surfaces then release the heat at night to keep the building warm. Similarly, absorbent plates on a roof can heat liquid in tubes that supply a house with hot water. Solar energy is lauded as an inexhaustible fuel source that is pollution and often noise free. The technology is also versatile. For example, solar cells generate energy for far­out places like satellites in Earth orbit and cabins deep in the Rocky Mountains as easily as they can power downtown buildings and futuristic cars. But solar energy doesn't work at night without a storage device such as a battery, and cloudy weather can make the technology unreliable during the day.

Which is more expensive source of electrical energy ?

Read the following passage carefully and answer the questions given below it.<br><br> Every year, the sun irradiates the land masses on earth with the equivalent of 19,000 billion tons of oil equivalent (toe). Only a fraction - 9 billion toe - would satisfy the world's current energy requirements. Put differently, in 20 minutes, the amount of solar energy falling on the earth could power the planet for one year. Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year. Solar energy is the technology used to harness the sun's energy and make it useable. Today, the technology produces less than one tenth of one percent of global energy demand. All energy originates with the sun except for nuclear, geothermal and tidal energy. Solar energy comes to us as high intensity radiation (light energy). As it falls on the earth, it is transformed into heat by any surface or material - be it the atmosphere, soil, buildings, or even the furniture in front of a window. This heat also drives the world's weather systems including wind, rain and river flow. <br><br> Through photosynthesis, plants also turn solar energy into new growth. Many people are familiar with so­ called photovoltaic cells, or solar panels, found on things like spacecraft, rooftops, and handheld calculators. The cells are made of semiconductor materials like those found in computer chips. When sunlight hits the cells, it knocks electrons loose from their atoms. As the electrons flow through the cell, they generate electricity. Photo­voltaic were initially, and still are, used to power small and medium­sized applications, from the calculator powered by a single solar cell to off­grid homes powered by a photovoltaic array. They are an important and relatively inexpensive source of electrical energy where grid power is inconvenient, unreasonably expensive to connect, or simply unavailable. However, as the cost of solar electricity is falling, solar power is also increasingly being used even in grid­connected situations as a way to feed low­carbon energy into the grid. On a much larger scale, solar thermal power plants employ various techniques to concentrate the sun's energy as a heat source. The heat is then used to boil water to drive a steam turbine that generates electricity in much the same fashion as coal and nuclear power plants, supplying electricity for thousands of people. In one technique, long troughs of Ushaped mirrors focus sunlight on a pipe of oil that runs through the middle. The hot oil then boils water for electricity generation. Another technique uses movable mirrors to focus the sun's rays on a collector tower, where a receiver sits. Molten salt flowing through the receiver is heated to run a generator. Other solar technologies are passive. For example, big windows placed on the sunny side of a building allow sunlight to heat­ absorbent materials on the floor and walls. These surfaces then release the heat at night to keep the building warm. Similarly, absorbent plates on a roof can heat liquid in tubes that supply a house with hot water. Solar energy is lauded as an inexhaustible fuel source that is pollution and often noise free. The technology is also versatile. For example, solar cells generate energy for far­out places like satellites in Earth orbit and cabins deep in the Rocky Mountains as easily as they can power downtown buildings and futuristic cars. But solar energy doesn't work at night without a storage device such as a battery, and cloudy weather can make the technology unreliable during the day.

Which of the following is not a Source of Energy ?