This document discusses nuclear fission and fusion reactions, as well as key concepts like critical mass. It also covers nuclear reactors, their components, and different types classified by neutron energy/moderator used and fuel. The document compares fission and fusion in terms of fuel sources and byproducts. It then discusses solar energy conversion methods like thermal and photovoltaic, and applications like solar water pumps. In the end, it briefly introduces other renewable sources like wind and biomass energy.

2.  The process of splitting of heavier nucleus into
two or more smaller nuclei with simultaneous
liberation of large amount of energy

3. Process of combination of lighter nuclei into
heavier nucles with simultaneous liberation of
large amount of energy.

4.  The fission reaction where the neutrons from
the previous step continue to propagate and
repeat the reaction is called nuclear chain
reaction

5.  Critical Mass: The minimum amount of
fissionable material required to continue the
nuclear chain reaction is called critical mass.
 Super critical mass: If the mass of fissionable
material is more than the critical mass it is called
super critical mass
 Sub-critical mass: If the mass of fissionable
material is smaller than the critical mass it is
called sub-critical mass

6.  235U is limited
 danger of
meltdown
 toxic waste
 thermal pollution
 fuel is abundant
 no danger of
meltdown
 no toxic waste
 not yet sustainable
C. Johannesson
F
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O
N
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N

7.  Uncontrolled Nuclear fission
reaction: Atomb Bomb
 Controlled Nuclear fission reaction:
Nuclear Reactor

8.  The arrangement or equipment used to
carryout fission reaction under controlled
conditions is called a nuclear reactor.
 Classification :
 Based on Neutron Energy and modrator
 Based on Fuel used
 Based on purpose

10.  Fuel Rods : U235; Pu239
 Control Rods: Cd113;B10
 Moderators : heavy water,graphite
 Coolants: water,ilquid metal(Na or K)
 Ressure vessel
 Protective shield
 Turbine

11. Reactor which converts non-fissionable
material(U238,Th232) into fissionable
material(U235,Pu239).The reactor produces or
breeds more fissionable material than it
consumes.
U238+n0
1
→Pu239+2e-
fissionable
Pu239+n0
1
→Fission products+3n0
1

13.  Energy obtained directly from the sun light is
called solar energy.
 The nuclear fusion reaction is occurring inside
the sun release enormous amount of energy in
the form of heat and light.
 Solar energy is called as Primary resource,
because it is obtained from the environment.

14.  Thermal conversion:
 Thermal conversion involves conversion of light into
thermal (heat) energy.
 Absorption of thermal energy in the form of IR
radiation and it is useful for heating buildings.
 Solar energy is used for providing low temperature
heat.
 Solar heat collectors:
Solar heat collectors consist of natural materials like
stones, glass which can absorb heat during the day
time and release it slowly at night.

16.  It consists of an insulated box which is coated
with black paint.
 Sun light falling on black surface is readily
absorbed and converted into heat.
 Inside the box it has black painted copper coil,
through which coldwater tank, water is
supplied through pipes.

20.  Photo conversion involves conversion of light
energy directly into electrical energy with the
help of solar cell.
 Methods of photo conversion :
Solar cell or photo galvanic cell

21. Solar cells
 A solar cell (also called photovoltaic cell or
photoelectric cell) is a solid state electrical device that
converts the energy of light directly into electricity by
the photovoltaic effect.
 Solar cell consist of p-type semi conductor (such as Si
doped with B) and n-type semi conductor (such as Si
doped with P).
 When solar rays fall on the outer layer of n-type semi
conductor ,the electrons in the valence band get
promoted to the conduction band. The conduction
electrons cross the p-n junction and go to the p type
semiconductor.

22.  A potential difference between two layers is created.
 This potential difference cause flow of electrons.
 When p and n layers are connected to an external circuit,
electrons flow from n to p layer and hence current is
generated.
 Each cell=0.5 volts.
 Battery needed as storage

23. Solar water pump :
 Solar water pumps have been in mass
production since 1983 and are in use in
thousands of locations around the world.
 Pumps that are designed to be powered by
solar energy are far more efficient than an
equivalent AC powered pump.
 There are many types of pumps and systems
available for pumping from deep wells,
shallow wells, ponds and streams.

25. Solar car

29.  Solar energy are non-pollutable and eco-
friendly.
 They are also used in remote areas.
 It is one of the renewable sources of energy.

31.  Moving air is called
wind.
 Energy derived
from the force of the
wind is called wind
energy.

32. The strike of blowing wind on the blades of the wind
mill makes it rotating continuously.

33. COMPONENTS:
1.Propeller
blades(turbine)
2.Generator
3.Supporting structure

34. Wind Turbines: Number of Blades
Wind mill consists of large sized propeller blades which are connected
to a generator.
 Most common design is the three-bladed turbine. The most important reason
is the stability of the turbine. A rotor with an odd number of rotor blades (and at
least three blades) can be considered to be similar to a disc when calculating the
dynamic properties of the machine.
The minimum wind speed is 15km/hour.

35. HAWT: VAWT: Vertical A

37. WIND FARM - SMALL TURBINES:
 High costs for foundations for large turbines may not be economical
in some areas.
 Landscape considerations.

38. • Wind power generators
convert wind energy
(mechanical energy) to
electrical energy.
• The generator is attached
at one end to the wind
turbine, which provides the
mechanical energy.
• At the other end, the
generator is connected to
the electrical grid.
• The generator needs to
have a cooling system to
make sure there is no
overheating.

39.  Wind mills are capable of generating about 100 KW
electricity.

40.  The U.S. currently has more than 1,600 MW of installed
capacity and produces about 3 billion KWh of electricity each
year.
 More than 90 percent of this power is produced by three
wind farms in California (Altamont Pass, Tehachapi and
Palm Springs).

41. A battery is an arrangement of
several electrochemical cells
connected in series that can be
used as a source of direct
electric current.

42.  In these cells, the electrode reactions can not be
reversed by
 passing an external energy.
 The reaction occur only once and after use they
become dead therefore ,they are not chargeable
 E.g Dry cell,mercury cell

43.  In these cells, the electrode reactions can be
reversed by
 passing an external energy.
 They can be recharged by passing electric
current.
 They are called storage cells or accumulators.
 Ex: Lead acid storage cell, Nickel- cadmium
cell.

44.  In these cells the reactant , product and
electrolytes are continuously passing through
the cell here chemical energy get converted in
to electrical energy
 E.g hydrogen oxygen fuel cell

45.  Here the powdered zinc is mixed with KOH and MnO2
to get a gel
A Carbon rod acts as cathode. IT is immersed in KOH
The outside cylindrical body is made up of zinc
 Cell reactions
Alkaline battery
 At anode
Zn(s) + 2OH-
(aq) Zn(OH)2(s) +2e-
 At cathode
2MnO2(s) + H2O(l) +2e- Mn2O3(s) +2OH-
(aq)
 Overall reaction
Zn(s) +2MnO2(s)+ H2O(l) Zn(OH)2(s) + Mn2O3(s)

47.  Storage cell:
 A lead storage cell is secondary battery
which can operate both as a voltaic cell and as
an electrolytic cell when its act as a voltaic cell
it supplies electrical energy and becomes run
down .
 When its recharged , the cell operates as an
electrolytic cell.

49.  Anode
Lead - Pb
Cathode
Lead Oxide PbO2
Electrolyte
Sulphuric acid - H2(SO)4
 Description:
It consists of number of voltaic cells connected in series
 Pb is anode and PbO2 is cathode
Number of Pb plates and PbO2 plates are connected in
 parallel.
Plates are separated from adjacent ones by insulators
 like rubber or glass fiber.
This arrangement is immersed in dil. H2SO4

51. Advantages:
(i). It is made easily.
(ii). It produces very high current.
(iii). Effective one at low temperature.
(iv). Self- discharging rate is low.
Uses:
(i). Used in automobiles like Car, Bus, Van, Lorry,
Bike etc.
(ii). Used in Hospitals, Power stations, Telephone
exchanges etc
It is used to supply current mainly in automobiles
such as cars. Buses, trucks, etc.,
It is also used in gas engine ignition, telephone
exchanges, hospitals, power stations

52.  Description
Cd/Cd(OH)2//KOH(aq)/NiO2/Ni
 Anode -Cadmium (Cd)
 Cathode -A metal grid containing a paste of
NiO2
 Electrolyte -KOH

53.  At anode
 Cd(s) +2OH- discharging Cd(OH)2(s) +2e-
 at cathode charging
NiO2(s)+2H2O+2e- discharging Ni(OH)2(s)+2OH-
charging
 overall reaction(discharging)
Cd(s)+NiO2(s)+2H2Odischarge
Cd(OH)2(s)+Ni(OH)2(s)+Energy
charging

54.  Lithium Battery
It is a solid state battery. Solid electrolyte is used.
 Construction
It has a lithium anode and a TiS2 cathode. A solid electrolyte, a polymer,
is packed in between the electrodes. The polymer electrolyte permits the
passage of ions but not that of electrons.
Working (Discharging)
The anode is connected to cathode through the polymer electrolyte.
Lithium ions and electrons are produced at the anode . The cathode
receives the lithium ions and electrons.
 Description
It consists of a lithium anode and a TiS2 cathode. A solid electrolyte
generally a polymer is packed in between the electrodes.
 The electrolyte permits the passage of ions but not electrons.

55.  Cell reactions

56.  The battery is recharged by passing an
external current, which drives the lithium ions
back to the anode. The overall reaction is
LiTiS2 Li+ + TiS2

57.  Uses
Button sized batteries are used in calculators,
watches,
cameras, mobile phones, laptop computers

58.  Definition
Fuel cell is a voltaic cell. It converts chemical
energy of the fuels directly into electricity
without combustion. In these cells, the
reactants and electrolytes are continuously
supplied to the cell.
Fuel + Oxygen Oxidation products +
Electricity.

59.  Hydrogen - oxygen fuel cell
It is the simplest and most successful fuel
cell. The fuel-hydrogen and the oxidiser-
oxygen and the liquid electrolyte are
continuously supplied to the cell.
 Description
The cell has two porous electrodes, anode
and cathode. The electrodes are made of
compressed carbon containing a small amount
of catalyst (Pt, Pd, Ag). Between the two
electrodes an electrolytic solution, 25% KOH is
filled.

61.  Working
Hydrogen passes through the anode
compartment, where it is oxidised. Oxygen
passes through the cathode compar tment,
where it is reduced.
(Hydrogen – Oxygen fuel cell)

63.  They are efficient and instant in operation.
 They are pollution free.
 They produce electric current directly from
the reaction of a fuel and an oxidiser.
 They are light in weight

64.  Fuel cells cannot store electric energy.
 Electrodes are expensive and short lived.
 H2 should be pure.

65.  H2 - O2 fuel cells are used in space crafts,
submarines to get electricity
 In H2 - O2 fuel cell, the produt water is a
valuable source of fresh water for astronauts