Q1. A machine/An engine required to rotate the generator.
Turbine
Updated on: 2026-03-31 | Author: Rahul Patil
Turbine
A silicon solar cell of dimension 1 sq.cm. generates 0.5 V potential difference.
A silicon solar cell of dimension 1 sq.cm. generates a current of about 30 mA.
| Advantages of hydroelectric power plant | Disadvantage of hydroelectric power plant |
| i. No fuel is burnt in a hydroelectric power plant. Thus, no air pollution due to combustion of fuel occurs. | i. Villages, towns, forests may submerge due to back-water caused by the storage of water in dams. This leads to forced migration of the living population in that area. |
| ii. Electricity can be generated whenever required if the dam has sufficient water storage. | ii. The obstruction of the flow of river water may have adverse effect on the living world in the river. |
| iii. During rainy season, the water in the water reservoirs can be replenished and used for power generation. |
| Limitations of Solar energy | Limitations of Wind energy |
| Solar energy is difficult to employ. | Wind velocity necessary for wind-energy generation is not available everywhere |
| Solar energy cannot be used at night or on cloudy days. | The wind velocity at specific locations depends on many geographical factors |
| Solar energy is not available uniformly during the day time and at all the places on the earth. | Wind velocity is usually high on sea shores and therefore that environment is more appropriate for the installation of wind turbines |
It is the principle invented by Michael Faraday. According to this principle, whenever magnetic field around a conductor changes, a potential difference is generated across the conductor.
A sudden change that occurs in the nucleotide sequence of a gene, causing either a minor or considerable change in the characters of an individual is known as mutation.
In nuclear fission, the atom of a heavy element is bombarded by a neutron to form an unstable isotope which further splits into two or more smaller nuclei releasing extra neutrons and large amount of energy and heat.
| Electricity generation from solar cells | Solar thermal power generation | |
| i. | Solar radiation energy is converted directly into electrical energy. | The energy in solar radiation is first converted into thermal energy and then converted to electrical energy through various stages. |
| ii. | The electrical energy is generated directly by the photovoltaic effect. | The electrical energy is generated using reflectors, condenser, cooling tower, turbine and generator. |
| Thermal power plant | Solar thermal power plant | |
| i. | For thermal electricity generation, a non-renewable energy source i.e., coal is used. | For solar thermal electricity generation, renewable energy resource i.e., sunlight is used. |
| ii. | Thermal electricity generation causes air pollution. | Solar thermal electricity generation does not cause air pollution. |
| iii. | Heat energy obtained from burning fossil fuels is used to generate electricity. | Heat energy obtained from solar radiation is used to generate electricity. |
| iv. | Chemical energy of coal is converted into electrical energy through various stages. | Heat energy of sunlight is converted into electrical energy through various stages. |
| v. | Energy generated is not green energy. | Energy generated is green energy. |
True
True
Burning of fossil fuels like coal, and natural gas leads to emission of certain gases and soot particles. This results in air pollution.
Disposal of nuclear waste and the possibility of disaster due to accidents in nuclear power plants are the drawbacks associated with the generation of energy using nuclear power plants.
Burning of fossil fuels like coal, natural gas leads to the emission of harmful gases like carbon monoxide, nitrogen dioxide causing air pollution.
The reserves of fossil fuels are limited which are going to get depleted in the future.
Thus, as the generation of energy from fossil fuels is not an example of green energy.
| Conventional sources of energy | Non-conventional sources of energy | |
| i) | Conventional sources of energy are the sources that are commonly in use since a long time. | Non-conventional sources of energy refer to the sources that are identified a few decades ago. |
| ii) | Conventional sources of energy are limited and exhaustible. | Non-conventional sources of energy are abundant and inexhaustible. |
| iii) | They cause pollution. | They cause little or no pollution. |
| iv) | Fuels produced from conventional sources are comparatively expensive. | Fuels produced from non-conventional sources are comparatively cheaper. |
| v) | Conventional sources do not produce green energy. | Non-conventional sources produce green energy. |
| vi) | They are primarily used for industrial and commercial purposes. | They are mainly used for domestic purposes. |
| vii) | Example: fossil fuels such as coal, natural gas, etc. | Example: wind energy, solar energy, etc. |
Electricity generation using wind energy is done with the help of a wind turbine.
A wind turbine is a machine used to convert the kinetic energy of the wind to electrical energy.
A wind turbine consists of rotating blades, a gear box and a generator.
When the wind strikes the blade of the turbine, the blades rotate.
The axle of the turbine is connected to the electric generator through a gear box.
The gear box is used to increase the rotations per unit time.
In this way, the rotating blades run the turbine which in turn drives the generator to produce electricity.
Plutonium
Edible oil
Nuclear energy
Silicon
Solar Photovoltaic cell
Explanation:
The Solar Photovoltaic cell differs in that it turns sunlight directly into electricity using the photovoltaic effect. In contrast, the other options—electricity generation using wind energy, hydroelectric power plant, and solar thermal power plant—require mechanical or thermal energy conversion operations before producing electricity.
Fossil fuel
Mechanical energy, chemical energy, sound energy, light energy, heat energy.
Due to high energy consumption, the existing sources of energy are depleting rapidly and will become scarce in the future.
Saving energy will reduce the burning of fossil fuels, thus minimizing air pollution, water pollution, and the production of harmful gases that lead to environmental hazards such as global warming and acid rain.
The sources of energy which are being produced continuously in nature and are inexhaustible, i.e., they are always available for use are called renewable sources of energy.
Hydropower, solar energy, wind energy are produced from energy sources like water, sunlight and wind respectively that are produced continuously in nature and will not get depleted.
Thus, hydropower, solar energy and wind energy are called renewable energy.
Solar photovoltaic cells which have energy producing capacity of mW, are connected in required series and parallel combinations to form a solar panel.
Many solar panels are connected in series to form a solar string and many solar strings are connected in parallel to form a solar array which has energy producing capacity of MW.
Thus, with the required series and parallel combination of solar photovoltaic cells to form solar panels, solar strings, and solar arrays, it is possible to produce energy from mW to MW capacity.
In a power plant, a turbine is used to rotate the generator which produces the energy.
To drive the turbine, we need an energy source.
The construction of the turbine in a power plant depends on the type of energy source which is being used to rotate the turbine. For example, steam turbine is used in thermal power plant where steam is used to rotate the turbine while wind turbine with large fins is used in electricity generation using wind energy.
One kind of chain reaction is the nuclear fission reaction.
Nuclear power plants closely regulate these reactions.
Neutron production may increase uncontrollably if these reactions are not adequately regulated.
In nuclear power plants, the fission reaction must be strictly controlled because each released neutron triggers the fission of three uranium (U-235) atoms. Uncontrolled reactions can result in dangerous accidents.
Hydroelectric power station : Water stored in dams : : Nuclear power station : Uranium
True
True
In fuels coal and natural gas, natural gas is more eco-friendly since it does not contain sulphur and the burning of natural gas results in less pollution.
In modern civilization, energy has become a primary need.
In nuclear power plants, neutrons are bombarded on atoms of Uranium - 235.
False
False
In the power plant based on nuclear energy, Steam turbine is used to rotate the generator.
Kinetic energy in flowing water drives turbines to generate electricity.
Tehri, Koyana, Srishailam, Nathpa Zakri
| Column A | Column B |
| 1) Polluting energy | b) thermal energy |
| 2) Environment friendly energy | c) wind energy |
| Column A | Column B |
| 1) Sunlight | b) Environment friendly energy |
| 2) Natural gas | c) Fossil fuel |
Most electric power plants are based on the principle of electromagnetic induction.
LPG and CNG
Kudankulam, Tarapur, Rawatbhata, Kaiga
The given machine is a steam turbine.
To rotate the generator which produces the electrical energy.
To drive the turbine, we need an energy source. The construction of the turbine in a power plant depends on the type of energy source which is being used to rotate the turbine. For example, steam turbine is used in a thermal power plant where steam is used to rotate the turbine.
Electrical energy is generated using wind mill.
The power station depends on wind velocity which in turn differs from location to location and depends on many geographical factors.
Yes. Energy generated through wind mill is environment friendly.
Power available from solar cells : DC : : power require to run domestic equipments : AC
Principle of Electromagnetic induction was invented by the scientist Michael Faraday.
Solar photovoltaic cells convert the solar radiation energy directly into electrical energy.
Explanation:
Solar photovoltaic cell converts the solar radiation energy directly into electrical energy. This is called solar photovoltaic effect. The electrical energy generated through this energy transformation process is DC in nature.
These solar cells are made of a special type of material called semiconductor (e.g. silicon).
The inverter is an electronic device that converts DC solar power to AC power which is required to run most of the equipment in domestic and industrial use.
Stove : Thermal energy : : Sewing machine : Mechanical energy
True
Vindhyanagar, Mundra, Tamnar, Chandrapur
False
True
Thermal power generation : Air pollution : : Nuclear power generation : Nuclear waste
Thermal power generation plant
Energy generated from sources which are unlimited and environment friendly is called green energy.
The solar panel consists of many reflectors that reflect and concentrate solar radiations on absorbers.
When a neutron is bombarded on an atom of uranium, 3 neutrons generated in this process.
Energy sources which are unlimited and environment friendly like wind, water reservoir, sunlight and bio-fuel are called as green energy sources.
In a nuclear power plant, uranium or plutonium are used as fuel.
True
In the nuclear reactor, nuclear fission of nuclei to atoms like uranium or plutonium occurs. Control rods are used to speed up or slow down the chain reaction.
1 kW to 7 MW
Lake tapping is a process in which a tunnel is dug out near the bottom of a lake upto the water-rock contact of the lake. The final layer of the rock is then blasted with the help of dynamite which provides the inflow of water into the tunnel with more speed.
It is done to facilitate the generation of electricity when the water level goes down in peak summer.
Thus, it also helps the areas suffering with drought due to scarcity of water during summer.
Improper nuclear-waste storage and disposal result in environmental contamination.
Accidental leakage of nuclear radiation can lead to lethal disaster.
Since no fuel is burnt in hydroelectric power generation, there is no pollution resulting from combustion of fuels.
If there is sufficient water storage in the dam, it is possible to generate electricity as and when necessary.
Although water reservoir is used for power generation, it can be replenished during rainy season, leading to uninterrupted power generation
Improper nuclear-waste storage and disposal can result in environmental contamination.
Accidental leakage of nuclear radiation can lead to lethal disaster.
A condenser is used to convert steam back to water by cooling it.
Generator is a machine that generates electrical energy.
Turbine is used to rotate the magnet in the generator.
The back-water due to storage of water in a dam may submerge villages or towns in that area. This leads to the problems of rehabilitation of the displaced population. Moreover, this can also submerge forests as well as fertile land.
The obstruction of the flow of river water may have an adverse effect on the living world in the river.