Textbook: Towards Green Energy | Science and Technology Class 10 (Maharashtra SSC Board) PDF Download

 Page 1


47
Let’s Discuss
 5. Towards Green Energy 
1. What is Energy?
2. What are different types of Energy?
3. What are different forms of Energy?
  Make a list of the work that we do in our 
day to day life using energy. Which forms of 
energy do we use to do this work? Discuss 
with your friends.
1. Where do we use electrical energy in our day-to-day life?
2. How Electric energy is produced ?
Make a table
Make a table based on forms of energy and corresponding devices.
 Generation of electrical energy
Ø 	Use of various energy sources 
Ø 	Generation of electrical energy
Ø 	Process of generation of electricity and environment
Can you recall?
Energy and use of energy
 In modern civilization, energy has become a primary need along with food, cloth and 
shelter. We need energy in different forms for diverse types of works. The energy that 
we need may be in the form of mechanical energy, chemical energy, sound energy, light 
energy or heat energy. How do we get these different forms of energy?
Can you tell?
 We know that energy can be converted from one form to another. Different sources of 
energy are used  to the different forms of energy necessary for us. In previous standards 
we have learnt about energy, sources of energy and various concepts related to them. 
Here we will learn about various sources that are now used for the generation of electrical 
energy, the methods that are used for this, the scientific principles that are used there, the 
advantages and disadvantages of these methods and also what is meant by green energy. 
Most of the electric power plants are based on the principle of electromagnetic induction 
invented by Michael Faraday. According to this principle, whenever magnetic field around 
a conductor changes, a potential difference is generated across the conductor. 
The field around a conductor can be changed in two ways. If a conductor is stationary 
and magnet is rotating, the field around the conductor changes or if a magnet is stationary, 
but the conductor is moving then also the field around the conductor will change. Thus, in 
both these cases, a potential difference is created across the conductor. (Figure 5.1). The 
electrical power generating machine based on this principle is called electric generator.
Page 2


47
Let’s Discuss
 5. Towards Green Energy 
1. What is Energy?
2. What are different types of Energy?
3. What are different forms of Energy?
  Make a list of the work that we do in our 
day to day life using energy. Which forms of 
energy do we use to do this work? Discuss 
with your friends.
1. Where do we use electrical energy in our day-to-day life?
2. How Electric energy is produced ?
Make a table
Make a table based on forms of energy and corresponding devices.
 Generation of electrical energy
Ø 	Use of various energy sources 
Ø 	Generation of electrical energy
Ø 	Process of generation of electricity and environment
Can you recall?
Energy and use of energy
 In modern civilization, energy has become a primary need along with food, cloth and 
shelter. We need energy in different forms for diverse types of works. The energy that 
we need may be in the form of mechanical energy, chemical energy, sound energy, light 
energy or heat energy. How do we get these different forms of energy?
Can you tell?
 We know that energy can be converted from one form to another. Different sources of 
energy are used  to the different forms of energy necessary for us. In previous standards 
we have learnt about energy, sources of energy and various concepts related to them. 
Here we will learn about various sources that are now used for the generation of electrical 
energy, the methods that are used for this, the scientific principles that are used there, the 
advantages and disadvantages of these methods and also what is meant by green energy. 
Most of the electric power plants are based on the principle of electromagnetic induction 
invented by Michael Faraday. According to this principle, whenever magnetic field around 
a conductor changes, a potential difference is generated across the conductor. 
The field around a conductor can be changed in two ways. If a conductor is stationary 
and magnet is rotating, the field around the conductor changes or if a magnet is stationary, 
but the conductor is moving then also the field around the conductor will change. Thus, in 
both these cases, a potential difference is created across the conductor. (Figure 5.1). The 
electrical power generating machine based on this principle is called electric generator.
48
5.1Electromagnetic Induction 
Rotating 
magnetic 
field 
Lines of flux
Induced 
emf 
Voltmeter 
Coil
High 
Velocity 
steam 
Nozzle
Blade
Wheel 
Shaft 
5.2 Steam turbine
5.3 Schematic of electric generator 
generated electrical 
energy
Rotating 
Electric 
magnet 
5.4 Flow chart showing generation of electrical energy
5.5 Flow chart showing generation of electrical energy using thermal energy 
Proper energy source to run turbine Turbine Electrical energy Generator
 Such large generators are used in commercial power generation plants. Turbine is used 
to rotate the magnet in the generator. A turbine has blades .When a flow of liquid or gas is 
directed on the blades of the turbine, it rotates (see Figure 5.2). because of the kinetic energy 
of the flow.This turbine is connected to electric generator. Thus the magnet in electric gener-
ator starts rotating and electric energy is produced (Fig.5.3)
This method of electric energy generation can 
be represented as below.
Thus, to generate electricity based on the 
principle of electromagnetic induction, we need a 
generator. To rotate the generator we need a turbine 
and to drive the turbine, we need an energy source. 
Based on which type of energy source is used to 
rotate the turbine, there are different types of power 
generating stations. The design of the turbine used 
in different types of power stations is also different.
Thermal energy based electric power station
In this the turbine is rotated using steam. Water is heated in a boiler. Using the ther-
mal energy released due to burning of coal. Steam of very high temperature and pressure 
is generated. The energy in the steam drives the turbine. Thus, the generator connected 
to the turbine rotates and electrical energy is produced. The steam is converted back into 
water and the water is re-circulated to the boiler. This is shown in flow chart in fig 5.5
Fuel Coal 
Boiler for conversion 
of water to steam 
Steam turbine
Generator
Electrical 
energy
System for converting steam back to water
Page 3


47
Let’s Discuss
 5. Towards Green Energy 
1. What is Energy?
2. What are different types of Energy?
3. What are different forms of Energy?
  Make a list of the work that we do in our 
day to day life using energy. Which forms of 
energy do we use to do this work? Discuss 
with your friends.
1. Where do we use electrical energy in our day-to-day life?
2. How Electric energy is produced ?
Make a table
Make a table based on forms of energy and corresponding devices.
 Generation of electrical energy
Ø 	Use of various energy sources 
Ø 	Generation of electrical energy
Ø 	Process of generation of electricity and environment
Can you recall?
Energy and use of energy
 In modern civilization, energy has become a primary need along with food, cloth and 
shelter. We need energy in different forms for diverse types of works. The energy that 
we need may be in the form of mechanical energy, chemical energy, sound energy, light 
energy or heat energy. How do we get these different forms of energy?
Can you tell?
 We know that energy can be converted from one form to another. Different sources of 
energy are used  to the different forms of energy necessary for us. In previous standards 
we have learnt about energy, sources of energy and various concepts related to them. 
Here we will learn about various sources that are now used for the generation of electrical 
energy, the methods that are used for this, the scientific principles that are used there, the 
advantages and disadvantages of these methods and also what is meant by green energy. 
Most of the electric power plants are based on the principle of electromagnetic induction 
invented by Michael Faraday. According to this principle, whenever magnetic field around 
a conductor changes, a potential difference is generated across the conductor. 
The field around a conductor can be changed in two ways. If a conductor is stationary 
and magnet is rotating, the field around the conductor changes or if a magnet is stationary, 
but the conductor is moving then also the field around the conductor will change. Thus, in 
both these cases, a potential difference is created across the conductor. (Figure 5.1). The 
electrical power generating machine based on this principle is called electric generator.
48
5.1Electromagnetic Induction 
Rotating 
magnetic 
field 
Lines of flux
Induced 
emf 
Voltmeter 
Coil
High 
Velocity 
steam 
Nozzle
Blade
Wheel 
Shaft 
5.2 Steam turbine
5.3 Schematic of electric generator 
generated electrical 
energy
Rotating 
Electric 
magnet 
5.4 Flow chart showing generation of electrical energy
5.5 Flow chart showing generation of electrical energy using thermal energy 
Proper energy source to run turbine Turbine Electrical energy Generator
 Such large generators are used in commercial power generation plants. Turbine is used 
to rotate the magnet in the generator. A turbine has blades .When a flow of liquid or gas is 
directed on the blades of the turbine, it rotates (see Figure 5.2). because of the kinetic energy 
of the flow.This turbine is connected to electric generator. Thus the magnet in electric gener-
ator starts rotating and electric energy is produced (Fig.5.3)
This method of electric energy generation can 
be represented as below.
Thus, to generate electricity based on the 
principle of electromagnetic induction, we need a 
generator. To rotate the generator we need a turbine 
and to drive the turbine, we need an energy source. 
Based on which type of energy source is used to 
rotate the turbine, there are different types of power 
generating stations. The design of the turbine used 
in different types of power stations is also different.
Thermal energy based electric power station
In this the turbine is rotated using steam. Water is heated in a boiler. Using the ther-
mal energy released due to burning of coal. Steam of very high temperature and pressure 
is generated. The energy in the steam drives the turbine. Thus, the generator connected 
to the turbine rotates and electrical energy is produced. The steam is converted back into 
water and the water is re-circulated to the boiler. This is shown in flow chart in fig 5.5
Fuel Coal 
Boiler for conversion 
of water to steam 
Steam turbine
Generator
Electrical 
energy
System for converting steam back to water
49
 If you see a thermal power station, you will observe two types of towers there. What 
are they? If you observe the schematic of the thermal power station in Figure 5.7 , you will 
get answer to this question.
 Compare the schematic of the thermal power station with the block diagram above 
and you will understand how the boiler, turbine, generator and the condenser are arranged 
in the power station. 
 After combustion of fuel (here, coal) in the boiler, the emitted gases are released to the 
atmosphere through very high tower. Once the turbine is rotated using the steam at high 
temperature and high pressure, steam temperature and pressure decreases. This steam is 
converted back to water by taking out heat from it (i.e.by cooling it) . This is done in the 
condenser using water in the cooling tower. The water in cooling tower is circulated through 
the condenser. Heat energy in the steam is given to the water and the steam condenses 
back to water. The heat absorbed by the water is then released to atmosphere through 
vapour and heated air through cooling tower.  Although, thermal power generation is a 
major way of electricity generation today, it suffers from certain problems
   Since thermal energy is used here to generate electrical energy, such power plants are 
called thermal power plants. In thermal power plants, the chemical energy in the coal is 
converted into electrical energy through several steps which are shown in figure 5.6.
Let's Think
1. Why the energy in the coal is called as   
     chemical energy?
2.  Why steam is used to rotate the turbine?
Use of ICT 
 Prepare a presentation about thermal power plant using computerized presenta-
tion, animation, video, pictures, etc. Send it to others and upload on You Tube. 
5.6 Energy transformation in thermal power plant
Chemical energy 
in coal
Thermal 
energy
Kinetic 
energy
 in steam
Kinetic Energy 
in turbine
Electrical 
energy
Stack
Combustion gases to stack
Boiler
Fuel
Air
Turbine
Generator
Condenser
Warm water
Cooling tower
Pump
Cooled water
Pump
5.7 Schematics of Thermal power plant 
vapour and hot air
Page 4


47
Let’s Discuss
 5. Towards Green Energy 
1. What is Energy?
2. What are different types of Energy?
3. What are different forms of Energy?
  Make a list of the work that we do in our 
day to day life using energy. Which forms of 
energy do we use to do this work? Discuss 
with your friends.
1. Where do we use electrical energy in our day-to-day life?
2. How Electric energy is produced ?
Make a table
Make a table based on forms of energy and corresponding devices.
 Generation of electrical energy
Ø 	Use of various energy sources 
Ø 	Generation of electrical energy
Ø 	Process of generation of electricity and environment
Can you recall?
Energy and use of energy
 In modern civilization, energy has become a primary need along with food, cloth and 
shelter. We need energy in different forms for diverse types of works. The energy that 
we need may be in the form of mechanical energy, chemical energy, sound energy, light 
energy or heat energy. How do we get these different forms of energy?
Can you tell?
 We know that energy can be converted from one form to another. Different sources of 
energy are used  to the different forms of energy necessary for us. In previous standards 
we have learnt about energy, sources of energy and various concepts related to them. 
Here we will learn about various sources that are now used for the generation of electrical 
energy, the methods that are used for this, the scientific principles that are used there, the 
advantages and disadvantages of these methods and also what is meant by green energy. 
Most of the electric power plants are based on the principle of electromagnetic induction 
invented by Michael Faraday. According to this principle, whenever magnetic field around 
a conductor changes, a potential difference is generated across the conductor. 
The field around a conductor can be changed in two ways. If a conductor is stationary 
and magnet is rotating, the field around the conductor changes or if a magnet is stationary, 
but the conductor is moving then also the field around the conductor will change. Thus, in 
both these cases, a potential difference is created across the conductor. (Figure 5.1). The 
electrical power generating machine based on this principle is called electric generator.
48
5.1Electromagnetic Induction 
Rotating 
magnetic 
field 
Lines of flux
Induced 
emf 
Voltmeter 
Coil
High 
Velocity 
steam 
Nozzle
Blade
Wheel 
Shaft 
5.2 Steam turbine
5.3 Schematic of electric generator 
generated electrical 
energy
Rotating 
Electric 
magnet 
5.4 Flow chart showing generation of electrical energy
5.5 Flow chart showing generation of electrical energy using thermal energy 
Proper energy source to run turbine Turbine Electrical energy Generator
 Such large generators are used in commercial power generation plants. Turbine is used 
to rotate the magnet in the generator. A turbine has blades .When a flow of liquid or gas is 
directed on the blades of the turbine, it rotates (see Figure 5.2). because of the kinetic energy 
of the flow.This turbine is connected to electric generator. Thus the magnet in electric gener-
ator starts rotating and electric energy is produced (Fig.5.3)
This method of electric energy generation can 
be represented as below.
Thus, to generate electricity based on the 
principle of electromagnetic induction, we need a 
generator. To rotate the generator we need a turbine 
and to drive the turbine, we need an energy source. 
Based on which type of energy source is used to 
rotate the turbine, there are different types of power 
generating stations. The design of the turbine used 
in different types of power stations is also different.
Thermal energy based electric power station
In this the turbine is rotated using steam. Water is heated in a boiler. Using the ther-
mal energy released due to burning of coal. Steam of very high temperature and pressure 
is generated. The energy in the steam drives the turbine. Thus, the generator connected 
to the turbine rotates and electrical energy is produced. The steam is converted back into 
water and the water is re-circulated to the boiler. This is shown in flow chart in fig 5.5
Fuel Coal 
Boiler for conversion 
of water to steam 
Steam turbine
Generator
Electrical 
energy
System for converting steam back to water
49
 If you see a thermal power station, you will observe two types of towers there. What 
are they? If you observe the schematic of the thermal power station in Figure 5.7 , you will 
get answer to this question.
 Compare the schematic of the thermal power station with the block diagram above 
and you will understand how the boiler, turbine, generator and the condenser are arranged 
in the power station. 
 After combustion of fuel (here, coal) in the boiler, the emitted gases are released to the 
atmosphere through very high tower. Once the turbine is rotated using the steam at high 
temperature and high pressure, steam temperature and pressure decreases. This steam is 
converted back to water by taking out heat from it (i.e.by cooling it) . This is done in the 
condenser using water in the cooling tower. The water in cooling tower is circulated through 
the condenser. Heat energy in the steam is given to the water and the steam condenses 
back to water. The heat absorbed by the water is then released to atmosphere through 
vapour and heated air through cooling tower.  Although, thermal power generation is a 
major way of electricity generation today, it suffers from certain problems
   Since thermal energy is used here to generate electrical energy, such power plants are 
called thermal power plants. In thermal power plants, the chemical energy in the coal is 
converted into electrical energy through several steps which are shown in figure 5.6.
Let's Think
1. Why the energy in the coal is called as   
     chemical energy?
2.  Why steam is used to rotate the turbine?
Use of ICT 
 Prepare a presentation about thermal power plant using computerized presenta-
tion, animation, video, pictures, etc. Send it to others and upload on You Tube. 
5.6 Energy transformation in thermal power plant
Chemical energy 
in coal
Thermal 
energy
Kinetic 
energy
 in steam
Kinetic Energy 
in turbine
Electrical 
energy
Stack
Combustion gases to stack
Boiler
Fuel
Air
Turbine
Generator
Condenser
Warm water
Cooling tower
Pump
Cooled water
Pump
5.7 Schematics of Thermal power plant 
vapour and hot air
50
Do you know?
Problems
1. Air pollution due to burning 
of coal: Burning of coal results 
in emission of gases like carbon 
dioxide, sulphur oxide and nitrogen 
oxide which are harmful to the 
health.  
2. Along with the emission of 
gases due to burning of coal, soot 
particles are also released into 
the environment. This may cause 
serious health problems related to 
the respiratory system.
3. The reserves of fuel used in this method i.e. coal are limited. Therefore, in future, 
there will be limitations on the availability of the coal.
Power plant based on Nuclear Energy
 In the power plant based on nuclear energy also , steam turbine is used to rotate the 
generator. However, here, the energy released by fission of nuclei of atoms like Uranium or 
Plutonium is used to generate the steam of high temperature and high pressure. The energy 
in the steam rotates the turbine, which in turn drives the generator producing electricity. 
The flow chart of nuclear power plant is shown in fig 5.8 .
 Thus, here nuclear energy is converted into thermal energy, thermal energy is 
converted into kinetic energy of steam, kinetic energy of steam is converted into kinetic 
energy of turbine and finally the kinetic energy of the turbine is converted into electrical 
energy .The step-by-step transformation of energy is shown in  figure 5.5. 
How does nuclear fission take place? Can you tell?
 When neutron is bombarded on atom of Uranium - 235 , it absorbs the neutron and 
converts into its isotope Uranium - 236.  Uranium - 236 being extremely unstable converts 
into atoms of Barium and Krypton through a process of fission releasing three neutrons 
and 200 MeV energy. The three neutrons generated in this process cause fission of three   
other Uranium - 235 atoms releasing more energy. 
5.8 Nuclear power plant   
Nuclear reactor 
for nuclear 
fission
System for steam 
generation from
water
Steam turbine
Generator
Electrical
 energy
Fuel: Uranium or Plutonium
System for conversion of steam back into water
5.9 Energy transformation in nuclear power plant 
Nuclear
 energy
Thermal 
 energy
Kinetic energy 
in steam
Kinetic energy 
in turbine
Electrical 
Energy
Place    State   Capacity (MW)
Vindhyanagar Madhya Pradesh  4760
Mundra  Gujarat   4,620
Mundra  Gujarat  4,000
Tamnaar  Chhattisgarh  3,400
Chandrapur  Maharashtra  3,340
Some major thermal power plants in India and 
their capacity
Page 5


47
Let’s Discuss
 5. Towards Green Energy 
1. What is Energy?
2. What are different types of Energy?
3. What are different forms of Energy?
  Make a list of the work that we do in our 
day to day life using energy. Which forms of 
energy do we use to do this work? Discuss 
with your friends.
1. Where do we use electrical energy in our day-to-day life?
2. How Electric energy is produced ?
Make a table
Make a table based on forms of energy and corresponding devices.
 Generation of electrical energy
Ø 	Use of various energy sources 
Ø 	Generation of electrical energy
Ø 	Process of generation of electricity and environment
Can you recall?
Energy and use of energy
 In modern civilization, energy has become a primary need along with food, cloth and 
shelter. We need energy in different forms for diverse types of works. The energy that 
we need may be in the form of mechanical energy, chemical energy, sound energy, light 
energy or heat energy. How do we get these different forms of energy?
Can you tell?
 We know that energy can be converted from one form to another. Different sources of 
energy are used  to the different forms of energy necessary for us. In previous standards 
we have learnt about energy, sources of energy and various concepts related to them. 
Here we will learn about various sources that are now used for the generation of electrical 
energy, the methods that are used for this, the scientific principles that are used there, the 
advantages and disadvantages of these methods and also what is meant by green energy. 
Most of the electric power plants are based on the principle of electromagnetic induction 
invented by Michael Faraday. According to this principle, whenever magnetic field around 
a conductor changes, a potential difference is generated across the conductor. 
The field around a conductor can be changed in two ways. If a conductor is stationary 
and magnet is rotating, the field around the conductor changes or if a magnet is stationary, 
but the conductor is moving then also the field around the conductor will change. Thus, in 
both these cases, a potential difference is created across the conductor. (Figure 5.1). The 
electrical power generating machine based on this principle is called electric generator.
48
5.1Electromagnetic Induction 
Rotating 
magnetic 
field 
Lines of flux
Induced 
emf 
Voltmeter 
Coil
High 
Velocity 
steam 
Nozzle
Blade
Wheel 
Shaft 
5.2 Steam turbine
5.3 Schematic of electric generator 
generated electrical 
energy
Rotating 
Electric 
magnet 
5.4 Flow chart showing generation of electrical energy
5.5 Flow chart showing generation of electrical energy using thermal energy 
Proper energy source to run turbine Turbine Electrical energy Generator
 Such large generators are used in commercial power generation plants. Turbine is used 
to rotate the magnet in the generator. A turbine has blades .When a flow of liquid or gas is 
directed on the blades of the turbine, it rotates (see Figure 5.2). because of the kinetic energy 
of the flow.This turbine is connected to electric generator. Thus the magnet in electric gener-
ator starts rotating and electric energy is produced (Fig.5.3)
This method of electric energy generation can 
be represented as below.
Thus, to generate electricity based on the 
principle of electromagnetic induction, we need a 
generator. To rotate the generator we need a turbine 
and to drive the turbine, we need an energy source. 
Based on which type of energy source is used to 
rotate the turbine, there are different types of power 
generating stations. The design of the turbine used 
in different types of power stations is also different.
Thermal energy based electric power station
In this the turbine is rotated using steam. Water is heated in a boiler. Using the ther-
mal energy released due to burning of coal. Steam of very high temperature and pressure 
is generated. The energy in the steam drives the turbine. Thus, the generator connected 
to the turbine rotates and electrical energy is produced. The steam is converted back into 
water and the water is re-circulated to the boiler. This is shown in flow chart in fig 5.5
Fuel Coal 
Boiler for conversion 
of water to steam 
Steam turbine
Generator
Electrical 
energy
System for converting steam back to water
49
 If you see a thermal power station, you will observe two types of towers there. What 
are they? If you observe the schematic of the thermal power station in Figure 5.7 , you will 
get answer to this question.
 Compare the schematic of the thermal power station with the block diagram above 
and you will understand how the boiler, turbine, generator and the condenser are arranged 
in the power station. 
 After combustion of fuel (here, coal) in the boiler, the emitted gases are released to the 
atmosphere through very high tower. Once the turbine is rotated using the steam at high 
temperature and high pressure, steam temperature and pressure decreases. This steam is 
converted back to water by taking out heat from it (i.e.by cooling it) . This is done in the 
condenser using water in the cooling tower. The water in cooling tower is circulated through 
the condenser. Heat energy in the steam is given to the water and the steam condenses 
back to water. The heat absorbed by the water is then released to atmosphere through 
vapour and heated air through cooling tower.  Although, thermal power generation is a 
major way of electricity generation today, it suffers from certain problems
   Since thermal energy is used here to generate electrical energy, such power plants are 
called thermal power plants. In thermal power plants, the chemical energy in the coal is 
converted into electrical energy through several steps which are shown in figure 5.6.
Let's Think
1. Why the energy in the coal is called as   
     chemical energy?
2.  Why steam is used to rotate the turbine?
Use of ICT 
 Prepare a presentation about thermal power plant using computerized presenta-
tion, animation, video, pictures, etc. Send it to others and upload on You Tube. 
5.6 Energy transformation in thermal power plant
Chemical energy 
in coal
Thermal 
energy
Kinetic 
energy
 in steam
Kinetic Energy 
in turbine
Electrical 
energy
Stack
Combustion gases to stack
Boiler
Fuel
Air
Turbine
Generator
Condenser
Warm water
Cooling tower
Pump
Cooled water
Pump
5.7 Schematics of Thermal power plant 
vapour and hot air
50
Do you know?
Problems
1. Air pollution due to burning 
of coal: Burning of coal results 
in emission of gases like carbon 
dioxide, sulphur oxide and nitrogen 
oxide which are harmful to the 
health.  
2. Along with the emission of 
gases due to burning of coal, soot 
particles are also released into 
the environment. This may cause 
serious health problems related to 
the respiratory system.
3. The reserves of fuel used in this method i.e. coal are limited. Therefore, in future, 
there will be limitations on the availability of the coal.
Power plant based on Nuclear Energy
 In the power plant based on nuclear energy also , steam turbine is used to rotate the 
generator. However, here, the energy released by fission of nuclei of atoms like Uranium or 
Plutonium is used to generate the steam of high temperature and high pressure. The energy 
in the steam rotates the turbine, which in turn drives the generator producing electricity. 
The flow chart of nuclear power plant is shown in fig 5.8 .
 Thus, here nuclear energy is converted into thermal energy, thermal energy is 
converted into kinetic energy of steam, kinetic energy of steam is converted into kinetic 
energy of turbine and finally the kinetic energy of the turbine is converted into electrical 
energy .The step-by-step transformation of energy is shown in  figure 5.5. 
How does nuclear fission take place? Can you tell?
 When neutron is bombarded on atom of Uranium - 235 , it absorbs the neutron and 
converts into its isotope Uranium - 236.  Uranium - 236 being extremely unstable converts 
into atoms of Barium and Krypton through a process of fission releasing three neutrons 
and 200 MeV energy. The three neutrons generated in this process cause fission of three   
other Uranium - 235 atoms releasing more energy. 
5.8 Nuclear power plant   
Nuclear reactor 
for nuclear 
fission
System for steam 
generation from
water
Steam turbine
Generator
Electrical
 energy
Fuel: Uranium or Plutonium
System for conversion of steam back into water
5.9 Energy transformation in nuclear power plant 
Nuclear
 energy
Thermal 
 energy
Kinetic energy 
in steam
Kinetic energy 
in turbine
Electrical 
Energy
Place    State   Capacity (MW)
Vindhyanagar Madhya Pradesh  4760
Mundra  Gujarat   4,620
Mundra  Gujarat  4,000
Tamnaar  Chhattisgarh  3,400
Chandrapur  Maharashtra  3,340
Some major thermal power plants in India and 
their capacity
51
5.10 Nuclear fission (Chain reaction)
Nuclear Fission 
Neutron absorption  
Internet is my friend
 Complete the following table for some 
important nuclear power plants in India.
Place  State           Capacity (MW)
Kudankulam .........  ..........
Tarapur  .........  ..........
Ravatabhata .........  ..........
Kaiga  .........  ..........
5.11 Schematic diagram of nuclear power plant
Observe the schematic of thermal power plant and the nuclear power plant. Discuss 
what are the similarities and differences between the two?
Compare
 The neutrons released in this reaction release more energy through fission of more 
uranium nuclei. This process of fission of  Uranium -235 atoms continues and is called 
the chain reaction. In nuclear power plants, a controlled chain reaction results in release 
of thermal energy, which is used for electric energy generation. 
A nuclear power plant does not use fossil fuel like coal. Therefore, problems like air 
pollution do not arise. Also, if sufficient nuclear fuel is available, this can be a good source 
of electrical energy. However, there are few problems associated with nuclear power 
generation.
Problems:
1.   The products after fission of nuclear fuel are also radioactive and emit harmful radiations. 
The products are called as nuclear waste. How to dispose the nuclear waste safely is a big 
challenge before the scientists.
2.    An accident in nuclear power plant can be very fatal. This is because the accident may 
result in release of very harmful radiations.
Cooling tower
Generator
Turbine 
Pump
Pump
Condenser
Boiler
Warm water
Nuclear 
reactor
Control pods