NON-CONVENTIONAL ENERGY SOURCES & STORAGE DEVICES. Nuclear energy-fission and fusion reactions and light water nuclear reactor for power generation

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1 NON-CONVENTIONAL ENERGY SOURCES & STORAGE DEVICES Syllabus & Course material: Nuclear energy-fission and fusion reactions and light water nuclear reactor for power generation (block diagram only) breeder reactor solar energy conversion solar cells wind energy fuel cells hydrogen- oxygen fuel cell batteries alkaline batteries lead-acid, nickel-cadmium and lithium batteries. 1

2 NON-CONVENTIONAL ENERGY SOURCES & STORAGE DEVICES INTRODUCTION: Non Conventional sources of energy are those which are being continuously produced in nature and non exhaustible. For example, solar energy, tidal energy, geothermal energy, wind energy, water energy, ocean energy, biogas energy, etc. Energy storage is the storing of some form of energy that can be drawn upon at a later time to perform some useful operation. A device that stores energy is sometimes called an accumulator. All forms of energy are either potential energy (eg. chemical, gravitational or electrical energy) or kinetic energy (eg. thermal energy). A wind up clock stores potential energy (in this case mechanical, in the spring tension), a battery stores readily convertible chemical energy to keep a clock chip in a computer running (electrically) even when the computer is turned off, and a hydroelectric dam stores power in a reservoir as gravitational potential energy. Even food is a form of energy storage, chemical in this case. Energy storage as a natural process is as old as the universe itself - the energy present at the initial creation of the Universe has been stored in stars such as the Sun, and is now being used by humans directly (e.g. through solar heating), or indirectly (e.g. by growing crops or conversion into electricity in solar cells). Energy storage systems in commercial use today can be broadly categorized as mechanical, electrical, chemical, biological, thermal and nuclear. Nuclear Energy is energy due to the splitting (fission) or merging together (fusion) of the nuclei of atom(s). The conversion of nuclear mass to energy is consistent with the mass-energy equivalence formula ΔE= Δm.c ², in which ΔE= energy release, Δm= mass defect, and c = the speed of light in a vacuum (a physical constant). Nuclear energy was first discovered by French physicist Henri Becquerel in 1896, when he found that photographic plates stored in the dark near uranium were blackened like X- ray plates, which had been just recently discovered at the time Nuclear energy used as a form of alchemy to turn lead into gold or change any atom to any other atom (albeit through many steps). Radionuclide (radioisotope) production often involves irradiation of another isotope (or more precisely a nuclide), with alpha particles, beta particles, or gamma rays. Iron has the highest binding energy per nucleon of any atom. If an atom of lower average binding energy is 2

3 changed into an atom of higher average binding energy, energy is given off. The chart shows that fusion of hydrogen, the combination to form heavier atoms, releases energy, as does fission of uranium, the breaking up of a larger nucleus into smaller parts. Stability varies between isotopes: the isotope U-235 is much less stable than the more common U-238. Nuclear energy is released by three exoenergetic (or exothermic) processes: Radioactive decay, where a neutron or proton in the radioactive nucleus decays spontaneously by emitting either particles, electromagnetic radiation (gamma rays), neutrinos (or all of them) Fusion, two atomic nuclei fuse together to form a heavier nucleus Fission, the breaking of a heavy nucleus into two (or more rarely three) lighter nuclei Nuclear Reactions During chemical reactions, electrons in the outermost orbits get involved and interchanged, but there no change in the nucleus. But nuclear reactions produce change in the nucleus, due to this an atomic charge occurs. The element loses its identity and becomes another element. This is called transmutation. The energy involved in a nuclear reaction is million times greater than that in chemical reaction. When the nuclear change occurs spontaneously, the element is said to undergo natural radioactivity. When the nucleus of one element is bombarded with another nucleus, the element may become radioactive, and changes to another element. In this case it is called artificial radioactivity. If the new element produced is not stable and undergoes further disintegration it is called induced radioactivity. Nuclear reactions are broadly classified into two categories: 1. Nuclear Fission 2. Nuclear Fusion Nuclear Fission When the heavy nucleus splits into two smaller fragments of approximately same masses, the nuclear reaction is called nuclear fission. When is bombarded with neutrons it is found to undergo fission as shown below. 3

4 The fission products are radioactive. They decay, by emitting β particles or neutrons and γ radiations and become stable nuclei. This fission of Uranium is carried out by relatively low energy neutrons. The points to remember about this fission reaction are: i. Specific fission fragments are not formed. ii. No unique products are formed. Several modes of fission for are possible. iii. Two groups of elements, one with masses from U and the other lighter group with U are produced. iv. The energy released from one fission is different form the energy released from another fission v. The number of neutrons released from varies from 1 to 4. vi. Average energy is released is 200 MeV. An induced nuclear fission event. A slow-moving neutron is absorbed by the nucleus of uranium 235 atom, which in turn splits into fast moving lighter elements (fission products) and free neutrons. 4

5 Nuclear Fusion Nuclear fusion is a combination of light - weight nuclei, with the simultaneous release of energy. For example, fusion reaction in sun may be: 5

6 DIFFERENCES BETWEEN NUCLEAR FISSION & FUSION S.No NUCLEAR FISSION NUCLEAR FUSION Heavy nucleus breaks up to form lighter nuclei It is a chain reaction Two lighter nuclei fuse together to form a heavy nucleus. It is not a chain reaction It is carried out by bombarding the heavy nuclei with neutrons. It is a controlled process It is carried out by heating the lighter nuclei to very high temperatures. It is control less process 5. Energy produced from this process is low. Nuclear Reactors Energy produced from this process is high. Nuclear reactors are ones in which nuclear fission is carried out in a controlled way. Two types of reactors are in use. (i) Thermal reactors (ii) Fast breeder reactors Thermal reactors In a thermal reactor, 235 U fission is carried out and the neutrons released are moderated by bombarding them against the nuclei or heavy water. The oxide of 235 U is used as nuclear fuel, in the form of aluminum plated rods. To reduce the rate of fission, if it becomes high, Cd rods are inserted. The heat generated is removed by circulating a liquid coolant, which is an alloy of sodium and potassium. The coolant carrying pipes from the reactor pass through water in a heat exchanger. Water takes up the heat and the steam produced is used for running the turbines. 6

7 Nuclear Reactor which consist of the following components namely 1.Reactor Core: In reactor core the controlled fission reaction is made to occur and which comprises the fuel elements, control rods, coolant and moderator. Fuel elements: Nuclear fuel is the fissionable material used in reactors for producing electricity by the fission process. Eg. Uranium metal or alloy, UO 2, UC or UC Moderator: Moderators are used to reduce the kinetic energy of fast fission neutrons in the reactor. Eg. Heavy water, Beryllium and Graphite 3.Coolants: These are used to reduce the intense heat produced during the fission reaction. Eg. Ordinary and heavy water, liquid metals like Na, Organic liquids like benzene, polyphenyls, gaseous coolants like air, CO 2 and He. 4.Control rods: The chain reaction is controlled by using control rods which are made up of neutron absorbing materials. Eg. Cd, B, 5.Reflector: Nuclear reflector which surrounds the reactor core and it reflects back the neutrons if they leak from the core. It also increases the average power output from the reactor. Eg. H 2 O, D 2 O, Be or Graphite. 6.Pressure-Vessel: It is designed to withstand the pressure up to 200 kg/cm 2. It covers the core, reflector and also provides the entrance and exit passage for coolant. 7.Shielding: Shielding has no part to play in the reactor but it is very much important to shield the neutrons, gamma rays coming out from the reactor which are harmful to human. This shielding which weakens the radiations emitted from the reactor. In high power reactors, there are two shields are used. (i)thermal Shield: It consists of cm thick iron or steel covering and is located around the core and capable of shielding the gamma rays and it can be cooled by the circulation of water. (ii)biological shield: It consists of several feet thick layer of concrete and surrounds the reactor core, reflector, and the thermal shield. It is capable of absorbing any gamma rays and neutrons coming out from the reactor. 8.Heat Exchanger: Heat exchangers which transfer the heat liberated from the reactor core to boil water and get steam at about 400 kg/cm 2. 7

8 9.Turbine: In heat exchanger, the steam at high pressure is generated which is used to operate a steam turbine. Due to the rotation of the steam turbine electricity is produced which is stored through the electric generator or dynamo fixed to the shaft of the turbine. BREEDER REACTOR Breeder reactor is the reactor where the conversion of non-fissionable fuels likes (primary fuel) are converted into the fissionable fuels like (secondary fuel or man-made fuel) and that has conversion factor above unity. The conversion factor can be defined as the ratio of the number of secondary fuel atoms produced to the number of primary fuel atoms consumed. Breeder reactors are of great significance and commercial importance due to this reason worldwide research is going on about the reactor. If India develops breeder reactor, that can utilize its vast 232 Th. SOLAR ENERGY: solar cells. The most abundant solar energy can be converted into very useful electrical energy by means of 8

9 Solar Cell: Solar cell is a photovoltaic cell which is capable of converting the solar energy in to electrical energy directly. Principle: In a photovoltaic cell, two types of semiconductors namely n-type( Si doped with P) and p-type semiconductors (Si doped with B) are arranged in close contact with each other. Due to the close contact, a limited extent of electrons (from the n-type semiconductor) and positive holes (from the p- type semiconductor) can cross the boundary or junction between the two types of semiconductors. Working: When solar energy (solar rays) falls on the surface of the p-type semiconductor, the electron form the valence band moves to the conduction band by absorbing the solar energy and it crosses the p- n junction thereby a potential difference takes place between the two layers. This potential difference is the reason for the migration of electrons between the layers.(electrical energy). The potential difference and hence current increases as more solar energy falls on the surface of the outer layer and excites more electrons. Thus, when terminals attached to the p and n layers are connected to an external circuit, electrons flow from n-layer to the p-layer, thereby electric current is generated. This type of device which convert directly the solar energy to electrical energy is called photovoltaic cell and the arrangement of large cells are called as solar battery. 9

10 A large number of solar cells are joined together in a definite pattern to get solar cell panel, which is capable of providing sufficient electric power to lift water from deep well or light in a house or to operate radio and TV etc., Advantages of Solar cells: (i) Solar cells can produce about 0.7 W of electricity on exposure to the sun. (ii) It does not need any focusing device because it has no moving parts and requires little maintenance. (ii) (iii) It provides a pollution free environment. These can be used in places where the transmission of power lines may be quite expensive. Applications of Solar cells: Solar Cells can be used in the followings (i) (ii) (iii) (iv) (v) (vi) Electric street light, For running pumps In calculators, electronic watches, radios, TV etc. To produce electricity To melt metals, for heating purposes, As a source of electricity in space craft and satellites. 10

11 Disadvantages of Solar Cells: It is only capable producing electricity during sunny days but in rainy days an alternate source of electricity is necessary. WIND ENERGY: Wind energy is the kinetic energy of the air due to its motion. Wind Mill is a simple machine, which works with the energy of flowing air or wind. It consists of large blades, mounted on the shaft on vertical poles. The shaft is connected to a crank, and the crank is connected to a dynamo (generator). When wind strikes against the blades, then these start rotating. The rotating blades, they turn the coil of a generator, thereby electricity is generated. The amount of electricity produced by a single wind mill is small, and it is not economically feasible. Consequently a number of wind mills are erected side-by-side over a large area of land which is known as wind energy farms. Limitations of Wind Energy: Wind flow, the speed of the wind varies with time and seasons, the kinetic energy of the wind can be utilized only at the site. The wind is an unpredictable one and no guarantee to get wind in all seasons and all places. Advantages of Wind Energy: It is a pollution free resource of energy at free of cost and it is inexhaustible source. 11

12 FUEL CELLS: A Fuel cell is the device which is capable of converting the chemical energy in to electricity directly. The essential process in a fuel cell is Fuel + Oxygen Oxidation Products + Electricity The most successful fuel cell is hydrogen-oxygen fuel cell. It consists of an electrolytic solution such as 25% KOH solution, and two inert porous electrodes. H 2 and O 2 gases are bubbled through the anode and cathode compartment respectively, where the following chemical reactions take place, Anode: 2H 2 (g) + 4 OH - (aq) 4 H 2 O (l) + 4 e - Cathode: O 2 (g) + 2H 2 O (l) + 4 e - 4 OH (aq) Net : 2H 2 (g) + O 2 (g) 2 H 2 O (l) The standard emf of the cell E o = E o ox + E o red = 0.83 V V = 1.23 V 12

13 In practice, the emf of the cell is 0.8 to1.0 V. It may be noted that the only product discharged by the cell is water. The large number of these fuel cells is stacked together in series to make a fuel cell battery or fuel battery. Requirements of electrodes: Electrodes should be very good conductors, good source or sink of electrons, they should not be affected by the electrolytes, heat or electrode reactions. In H 2 -O 2 are used as the fuels, the electrodes are made of either graphite impregnated with finely divided Pt, or a 75/25 alloy of Pd and Ag, or Ni. The most common electrolytes are KOH or H 2 SO 4 or ion exchange resin saturated with water. For low temperature operating fuel battery (-54 0 C to 72 0 C), potassium thiocyanate dissolved in liquid NH 3 is employed. Application: Hydrogen-Oxygen fuel cell is used as auxiliary energy source in space vehicles, submarine and military vehicles. This is due to its low weight and the product water is the good source of fresh water to the submarine and space divers. 13

14 BATTERIES: A battery is a device that stores chemical energy for later release as electricity. A battery can be defined as a electrochemical cell (combination of several electrochemical cells) can be used as a direct source of electric current at a constant voltage. Types of Batteries: (i) Primary battery or primary cell: In these types of batteries the cell reaction is not reversible, all the reactants are converted to products and no more electricity is produced and the battery is in dead condition. (ii) Secondary battery or secondary cell: In these types of batteries the cell reaction is reversible, which can be done by passing direct electric current in opposite direction. It may be used through a large number of cycles of charging and discharging. (iii) Flow battery and fuel cell: In these cells the reactants, products, electrolytes pass through the battery, which is like a electrochemical cell that converts chemical energy to electrical energy. Characteristics of Battery: (i) Voltage: Voltage of the battery depends on the emf of the cells which can be obtained by Nernst equation. E 0 cell = ( E 0 cathode E 0 anode ) (2.303 RT/ n F ) log Q = E 0 cell ( V/n) log [Products/Reactants] (ii) (iii) (iv) Standard Electrode potential (E 0 cell): If E cell is more, the E cell becomes higher and vice versa. Temperature: An increase in temperature decreases the value of E cell and vice versa. The current is the rate at which the battery discharging. A battery can deliver high current only if the transfer of the electron is fast. (v) The capacity of the battery depends on the size of the battery which is given by Faraday s relation; C capacity = w nf/m where w= mass of the active material, M= molar mass of active material. 14

15 ALKALINE BATTERIES: In alkaline batteries KOH is used as the electrolyte and Zn in powdered form is mixed with KOH to get a gel. Graphite rod is surrounded by a paste containing MnO 2 and the outside body is made up of Zn. Reaction at Cathode: 2 MnO 2 (s) + H 2 O (l) + 2 e - Mn 2 O 3 (s) + 2 OH - (aq) Reaction at Anode: Zn (s) + 2 OH (aq) Zn(OH) 2 (s) + 2 e - Net Reaction: Zn (s) + 2 MnO 2 (s) + H 2 O (l) Zn(OH) 2 (s) + Mn 2 O 3 (s) Advantages of Alkaline Battery: (i) (ii) (iii) Zn does not dissolve in basic medium It maintains better voltage as the current drawn from it and the life of the alkaline battery is longer than dry cell, since there is no corrosion of Zn. Uses: Alkaline batteries are used in camera exposure controls, calculators, watches etc. Lead acid battery (Lead acid accumulator) or Acid storage cell These batteries were developed sometimes back and are now used very widely. The design does not change drastically. Modification and improved versions have flooded the market. Once it was thought that these batteries using an electrolyte solution cannot be sealed airtight. But recently sealed lead acid batteries have been developed. Construction Lead grids are coated with a paste consisting of lead monoxide (PbO) and dilute sulphuric acid (22%). One set of grids is connected together to a common terminal; similarly another set is connected to another terminal. The two set a are arranged such that plates of one set are adjacent to the plates of the other set. Porous PVC diaphragm sheets are placed intermittently, separating one plate from the other eclectically. 15

16 The assembly is housed in an ebonite or PVC container. The container is then filled with dilute sulphuric acid. The container is closed by a lid which is provided with holes for filling up of acid. First Charge The terminal of one set of plates is connected to the positive and other set to the negative terminals of a DC rectifier. A suitable current under a suitable voltage is passed for the required time. During this charge, lead monoxide coating on the set of plates connected to the terminal of the rectifier is oxidized to porous, spongy, and electro active lead dioxide. The lead dioxide coating present on the other set of plates connected to the negative terminal is reduced to porous, spongy, and elctroactive lead. Now the battery is ready for use that is discharge. (+) Oxidation PbO 2 PbO Reactions during discharging: (-) Reduction At anode (oxidation of Pb) Lead is oxidized to Pb 2+ ions, which further combines with SO 4 2- forms insoluble PbSO 4 Pb Pb Pb e - Pb 2+ + SO 4 2- Pb + SO 4 2- PbSO 4 + 2e - PbSO 4 + 2e- At cathode (reduction of PbO 2 ) PbO 2 is reduced to Pb 2+ ions, which further combines with SO 4 2- forms insoluble PbSO 4 PbO 2 + 4H + + 2e - Pb 2+ SO 4 2- PbO 2 + 4H + + SO e - Pb H 2 O PbSO 4 PbSO 4 +2H 2 O The overall reaction during charging is, Pb + PbO 2 + 2H 2 SO 4 2PbSO 4 + 2H 2 O + Energy 16

17 Lead sulphate is precipitated at both the electrodes. When 21.4% H 2 SO 4 is used as an electrolyte at 25 0 C, the voltage is about 2.0 V. Lead cell is commonly used in automobiles (combination six cells in series to form a battery with an emf of 12 V. Reactions during Charging: When an external emf greater than 2 V from generator is passed to the battery,(the positive pole of the generator is attached to the positive pole of the battery) the cell reaction get reversed. Reaction at the Cathode: PbSO e - 2- Pb + SO 4 Reaction at the anode: PbSO 4 + 2H 2 O + 2e - PbO H SO 4 Net chemical reaction: 2PbSO H 2 O + Energy Pb + PbO H SO 4 During charging process the concentration of the sulphuric acid increase, while during discharging process, the concentration of sulphuric acid decreases. Uses: Lead acid storage battery used in gas engine ignition, mines, laboratories, hospitals, broadcasting stations, automobiles, power stations etc. NICKEL CADMIUM (nicad) BATTERIES: Ni-Cd battery is the recently developed one and it is a portable, rechargeable and it has voltage about 1.4 V. This type of battery consists of a Cd anode and cathode composed of a paste of NiO (OH) (s). The cell reactions are At Cathode: 2 NiO(OH) (s) + 2 H 2 O (l) + 2 e - 2 Ni(OH) 2 (s) + 2 OH - (aq) At Anode: Cd (s) + 2 OH - (aq) Cd (OH) 2 (s) + 2 e - 17

18 Net Chemical reaction: 2 NiO(OH) (s) + Cd (s) + 2 H 2 O (l) Cd (OH) 2 (s) + 2 Ni(OH) 2 (s) The reaction can be readily reversed, because the reaction products, Ni(OH) 2 (s) and Cd (OH) 2 (s), adhere to the electrode surfaces. Uses: Nicad batteries are used in electronic calculators, electronic flash units, cordless electronic shavers, transistors and other battery powered small tools. LITHIUM BATTERY: It is a solid state and rechargeable battery with high voltage around 3.0 V, which consists of a lithium anode and titanium sulphide (TiS 2 ) as a cathode. A solid polymer is used as the electrolyte backed in between the two electrodes. The solid polymer (electrolyte) allows the passage of ions through two electrodes but not electrons. Reactions during discharging: When the anode and cathode are connected through an electrolyte (solid polymer), Li + ions move from anode to cathode and electrons generated at anode. The cathode receives Li + ions and electrons through external circuit. Reaction at cathode: TiS 2 (s) + e - TiS 2 18

19 Reaction at anode: Li (s) Li + + e - Net Reaction: Reactions during recharging: Li (s) + TiS 2 (s) Li + + TiS 2 (LiTiS 2 ) reaction is When an external current is passed to the battery, the Li + ions are converted into Li. The net LiTiS 2 Li + + TiS 2 Advantages of Li battery: Li battery generates a high voltage (3.0V) because it has electrodes potential (E 0 ) as negative. It can be made in various shapes and sizes. There is no risk of leakages from it because all its constituents are solid. Uses: Li battery is used in calculators, electronic flash units, transistors, headphones and cordless appliances. Quiz: 1. Batteries are the storage houses for a) Mechanical energy b) Electrical energy c) Light energy d) Sound energy 2. The basic of battery technology is a) Conversion of chemical energy into electrical energy b) Conversion of electrical energy into chemical energy c) Conversion of chemical energy into light energy d) Conversion of electrical energy into mechanical energy 3. Find out the primary battery from the following a) Lead accumulator b) Ni-Cd battery c) Hydrogen oxygen fuel cell b) Dry cell 4. Find out the secondary battery from the following a) Hydrogen oxygen fuel cell b) Mercury cell c) Lead acid battery d) Dry cell 19

20 5. Battery contains a) One anode and one cathode b) Two anodes c) More anodes and cathodes d) Two cathodes 6. Find out the anode and cathode in the lead acid battery a) Pb & PbO2 b) Pd & PdO2 c) Pb & PbO d) None of these. 7. The principle of primary battery is a) Reaction is reversed when passing electrical energy b) Reaction is not reversed when conducting chemical reaction c) Reaction is reversed during chemical reaction d) Reaction is not reversed when passing electrical energy 8. Which one is the reversible battery a) Primary battery b) Reserve battery c) Secondary battery d) Flow battery 9. In laclanche s cell the following is the electrolyte a) NH4Cl b)zncl2 c) MNo2 d) All the above 10. Find out the nature of the reaction Zn > Zn e - a) Oxidation b) Reduction c) Redox reaction d) None of these 11. Normally at anode the following reaction is possible a) Reduction b) Chemical c) Oxidation d) Redox reaction 12. In cold weather condition the following type of battery is preferable a) Primary battery b) H2 O2 fuel cell c) Alkaline battery d) Redox battery 13. Pb / PbSO4 it is a representation of a) Cathode b) Electrolyte c) salt bridge d) Anode 14. Lead acid battery produces electrical energy is (if it contains 6 cells) a) 12 V b) 6 V c) 8 V d) 24 V 15. Lead acid battery is used in a) Telephone exchange b) Power station c) Hospitals d) All the above 16. It is not an advantage of Ni- Cd battery a) Produces 1.4 V b) Smaller in size c) Weighter in weight d) Long life 20

21 17. What is the anode and cathode of Lithium battery a) Li & Tis b) Li & TiS2 c) Li & TiS3 d) Ti & LiS 18. In lithium battery electrolyte in the form of a) Liquid b) Gases c) Solid d) Plasma 19. Li generates higher voltage than other type of batteries because of a) Least negative E o value b) Most negative E o value c) Least positive E o value d) Most positive E o Value 20. Photo cell converts a) Electrical energy in to light energy b) Electrical energy into mechanical energy c) Light energy into electrical energy d) None of these 21. In P type semiconductor this kind of impurity is added, a) P b) Si c) B d) Mn 22. Solar cells can be used to produceh2 by a) Hydrolysis of water b) Electrolysis of water c) Neutralization of water d) Mineralization of water 23. Fuel cell is a electrochemical cell in which the chemical energy of the fuel is directly converted into electricity without a) Combustion b) Cooling c) Drilling d) Quenching 24. In H2 - O2 fuel cell this will be acts a s a oxidizer a) Hydrogen b) Oxygen c) KOH solution nitrogen 25. In H2 - O2 fuel cell this will acts as an electrolytic solution a) H2S b) Graphite c) 25% of KOH d) 40% of KOH 26. The structure of the nanoparticles is a) 10-6 m b) 10-8 m c) 10-9 m d) 10 9 m 27. It is not a method of production of carbon nanotubes a) Laser evaporation method b) Carbon arc method c) Carbon vapour deposition method d) Chemical vapour preposition method 28. By laser evaporation method can made µm long tubes. a) 10 µm b) 100 µm c) 1000µm d) µm 29. In laser evaporation method the graphite target is heated upto o C a) 100 o c b) 1000 o c c) 1200 o c d) 5000 o c 21

22 30. In carbon arc method carbon electrodes are separated by 1 mm at of following helium. a) 500 torr b) 50 torr c) 150 torr d) 550 torr 31. In chemical vapour deposition method hydrocarbon is decomposed at a) 1150 o c b) 1175 o c c) 1500 o c d) 1100 o c 32. Match the following a) CVD --- Carbon nanotube b) CNT --- Single walled carbon nanotube c) MWCNT --- Chemical vapour deposition d) SWCNT --- Multiwalled carbon nanotube a) b,d,c,a b) a,c,d,b c) b,d,c,a d) b,d,a,c 33. In 1856 faraday prepared colloidal gold it is also called as, a) Liquid metals b) Metal gold c) Divided metals d) All the above 34. In CVD method we can produce a tube like these a) With open ends b) With close ends c) With edge ends d) With corner ends 35. The following is used to discuss the electronic structure of carbon nanotubes a) MVS b) NMR c) ESR d) STM 36. The elastic flexibility of the carbon nanotube is more than that of a) Steel b) Iron c) Copper d) None of these 37. The carbon nanotubes are hard & stiff to bend because of, a) High young s modulus b) Low radius c) Low electrical property d) Low young s modulus 38. The nanotubes are bent, they does not break and can be straightened back into original stage without any damage. This is because of, a) Less amount of defect b) More defects c) No defects d) None of these. 39. Tensile strength of CNT is times more than that of steel. a) 2 times b) 5 times c) 12 times d) 20 times 40. Nanomaterials provide a) To transport electricity efficiently b) With lower cost transport c) To long distances d) All the above 41. Solar cells are used in boilers to produce a) Stream b) Cold water c) Hot water d) Pot water 22

23 42. Fuel cells converts a) Chemical energy into electrical energy b) Electrical energy into chemical energy c) Electrical energy into mechanical energy d) Light energy into electrical energy 43. Chirality tells about the a) How the tubes are rolled with respect to direction of T vector in graphite plane. b) How the tubes are rolled with respect to direction of H vector in graphite plane c) How the tubes are rolled with respect to direction of T vector in diamond plane. d) How the tubes are rolled with respect to direction of H vector in diamond plane 44. The change in nucleus takes place by (a) Chemical reaction (c) Rearrangement reaction (b) Nuclear reaction (d) None of the above 45. Slow neutrons can bring about the fission of (a) 90Th232 (b) 92U235 (c) 92U238 (d) 92Pb The material used to control neutron flux in an atomic reactor is (a) Heavy water (b) Paraffin (c) Cadmium (d) Graphite 47. The process 1H2 + 1H3 2He4 + 0n1 involves (a) Nuclear Fission (b) Chemical reaction (c) Spallation (d) Photochemical reaction(e) Nuclear Fusion 48. Choose the one, which is not used as moderators of neutrons in controlled chain reaction (a) Water b) Heavy water (c) Oxygen d) Graphite (e) Paraffin 49. Match the nuclear reactor components. A B a) Coolant e) H2O, D2O and Graphite b) Reflector f) Boron and Cadmium c) Control Rod g) H2O, D2O and CO2 d) Moderator h) Graphite, Be and D2O The correct matching is (a) a-h, b-e, c-f and d-g (c) a-f, b-h, c-e and d-g (b) a-e, b-f, c-g and d-h (d) a-e, b-g, c-f and d-h 50. A nuclear reactor is called breeder reactor when the conversion factor is (a) Zero (b) One (c) Less than one (d) greater than one 51. The order of the fission reaction 92U n1 55Cs Rb n1 + Energy is (a) Zero (b) One (c) Two (d) Pseudo first order 23

24 52. The principle involved in the atom bomb is (a) Nuclear Fission (b) Nuclear Fusion (c) Spallation (d) Both Nuclear Fission & Fusion 53. In alkaline battery, anode made up of (a) Zinc (b) Lead c) graphite (d) Cadmium 54. Sulphuric acid is used as an electrolyte in (a) Ni-Cd battery (b) Lead Storage battery (c) Fuel cell battery (d) Lithium battery (e) Both (b) and (c) is correct 55. The following one does not contains solid polymer electrolyte (a) Lithium battery (b) Flow type battery (c) Alkaline battery (d) Ni-Cd battery 56. The attraction behind the fuel cell is (a) Efficient energy conversion (c) low maintenance cost (e) All are incorrect 57. The current conduction in the solar cell is by (a) Movement of electron only (c) Movement of both electron and positive holes (b) High noise and thermal pollution (d) (a) and (c) both are correct (b) Movement of positive holes only (d) None of the above. 58. Which one of the principle involves in the wind energy mill (a) Conversion of kinetic energy to mechanical energy (b) Conversion of mechanical energy to kinetic energy (c) Conversion of chemical energy to kinetic energy (d) Conversion of kinetic energy to chemical energy ANSWERS: 1) b 2)a 3)d 4)c 5)c 6)b 7)d 8)c 9)d 10)a 11)c 12)c 13)d 14)a 15)d 16)c 17)b 18)c 19)b 20)c 21)c 22)b 23)a 24)b 25)c 26)c 27)c 28)b 29)c 30)a 31)d 32)d 33)c 34)a 35)d 36)d 37)a 38)c 39)d 40)d 41)c 42)a 43)a 44)b 45)b 46)c 47)c 48)c 49)d 50)b 51)b 52)b 53)a 54)c 55)c 56)d 57)c 58)a Assignment Questions: 1. Pb-Acid Storage battery 2. Solar Cell Principle, working and applications. 3. H2-O2 Fuel cell C0nstruction, working and applications. 24

25 4. Conventional Energy Resources Broad ideas. 5. Non-conventional Energy Resources Broad ideas. 6. Nuclear Energy and nuclear reactions. Model Questions: 1. Define nuclear fission? 2. Write any two examples for nuclear fission reaction? 3. Define nuclear fusion reaction? 4. Write any two examples for nuclear fusion reaction? 5. What is nuclear energy, compare with binding energy? 6. Differentiate nuclear fission from fusion reaction? 7. Discuss about nuclear stability and stability belt? 8. Give a brief note on nuclear reactor. 9. Write in detail about fast breeder test reactor. 10. Define conversion factor. 11. Write the role of coolants in nuclear reactors with few examples. 12. What are solar cells and explain its functions? 13. Give any two applications of solar cells. 14. What is wind energy and how it is converted into electrical energy? 15. What are fuel cells, give examples? 16. Describe about H 2 -O 2 fuel cell. 17. Write advantages and disadvantages of fuel cell. 18. Discuss in detail on non-conventional energy resources and storage devices. 19. Write about various types of batteries. 20. Write about primary battery or primary cell. 21. Write about secondary battery or secondary cell. 22. Write any few characteristics of battery. 23. Give a detail note on lead-acid battery. 24. Give a detail note on alkaline battery. 25. Give a detail note on Ni-Cd battery. 25

26 26. Give a detail note on Li battery. 27. Define the fuel cell. 28. Write the role of control rod and moderators in nuclear reactor. References 1. A Textbook of Engineering Chemistry by Shashi Chawla, 3 rd Edition, Dhanpat Rai & Co. (Pvt) Ltd., New Delhi. 2. A Textbook of Engineering Chemistry by Jain and Jain, 18 th Edition, Dhanpat Rai Publishing Company (Pvt) Ltd., New Delhi. 3. A Textbook of Engineering Chemistry by Jain and Jain, 15 th Edition, Dhanpat Rai Publishing Co. (Pvt) Ltd., New Delhi. 26