Category: Objective Questions

Molecular Biology Multiple Choice Questions on “Gene Regulation Ensures a Physiological Response”.

1. Regulation of enzyme activity is accomplished in ___________ steps.
A. 1
B. 2
C. 3
D. 4

Answer: B
Explanation: Regulation of enzyme activity plays a key role in governing the cell behavior. Thus its regulation comes in two specific steps. The first step is accomplished in part at the level of gene expression, which determines the amount of any protein synthesized by the cell. A further level of control is then obtained by regulation of protein function, which allows the cell to regulate not only the amount but also the activities of its proteins.

2. Binding of small molecules to enzymes leads to feedback inhibition.
A. True
B. False

Answer: A
Explanation: Conformational changes in the enzymes result from the binding of small molecules, such as, amino acids or nucleotides that regulate enzyme activity. This type of regulation commonly is responsible for controlling metabolic pathways by the process of feedback inhibition.

3. The regulatory molecules bind to the catalytic site of an enzyme to regulate its activity.
A. True
B. False

Answer: B
Explanation: Feedback inhibition is an example of allosteric regulation, in which a regulatory molecule binds to a site on an enzyme that is distinct from the catalytic site. The binding of such regulatory molecules alters the conformation of the protein, thereby changing the shape of the catalytic site and affecting catalytic activity.

4. Which of the following is incorrect about the inactive state of the Ras protein?
A. GDP bound form
B. Cell proliferation activation
C. Mutation leads to cancer
D. Changes configuration when bound to regulatory molecules

Answer: B
Explanation: Ras protein when bound to GDP, that is, in its inactive form, cannot activate cell proliferation. It can only activate cell proliferation when it is in the active GTP bound state.

5. The regulatory proteins bind to the enzymes with covalent linkages.
A. True
B. False

Answer: B
Explanation: The regulatory proteins bind to the enzymes with non-covalent linkages. Since no covalent bonds are formed, the binding of these regulatory molecules to the protein is readily reversible, allowing the cell to respond rapidly to environmental changes.

6. The activity of which of the following proteins is not regulated by covalent modifications?
A. Digestive enzymes
B. Apoptosis
C. Cell signaling
D. Blood clotting

Answer: C
Explanation: The activity of many proteins is regulated by covalent modifications. One example of this type of regulation is the activation of some enzymes by proteolytic cleavage of inactive precursors. Digestive enzymes and proteins involved in blood clotting and apoptosis are regulated in this mechanism.

7. Protein kinases transfer phosphate groups to the side chains of which of the following?
A. Serine
B. Valine
C. Glutamate
D. Lysine

Answer: A
Explanation: Protein phosphorylation is catalyzed by protein kinases, most of which transfer phosphate groups from ATP to the hydroxyl groups of the side chains of serine, threonine or tyrosine residues. The protein kinases are one of the largest protein families in eukaryotes, accounting for approximately 2% of eukaryotic genes.

8. Like kinases all phosphatases are also species specific in nature.
A. True
B. False

Answer: B
Explanation: Like protein kinases, most protein phosphatases are specific either for serine and threonine or for tyrosine residues. But some protein phosphatases can recognize all the three phosphoamino acids.

9. Which of the following is false about amino acid modification and activity?
A. Acetylation of lysine residue
B. Methylation of lysine and arginine residue
C. Glycosylation of serine and threonine residue
D. Nitrosylation of arginine residue

Answer: D
Explanation: Nitrosylation is the addition of NO groups to the side chains of amino acids. Nitrosylation generally occurs to the cystine residues of protein polypeptide chains and not arginine.

10. The cAMP-dependent protein kinase has how many subunits?
A. 1
B. 2
C. 3
D. 4

Answer: D

Molecular Biology Multiple Choice Questions on “Ti Plasmids are Transferred from Bacteria to Plants – 1”.

1. How many types of vector systems are used in eukaryotic plants?
A. 1
B. 2
C. 3
D. 4

Answer: C
Explanation: Three types of vector system have been used with varying degree of success:
i) Vector based on naturally occurring plasmid of Agrobacterium
ii) Direct gene transfer using various types of plasmid DNA
iii) Vectors based on plant viruses.

2. Ti plasmid is the only known plasmid of plant.
A. True
B. False

Answer: B
Explanation: There is no naturally occurring plasmid known in higher plants. The first known plasmid that is able to express itself in the plant is a bacterial plasmid known as Ti plasmid from the bacterium, Agrobacterium tumefaciens.

3. The Ti is referred to as _____________
A. Translocation inducing
B. Transfer inducing
C. Tumor inducing
D. Translation inducing

Answer: C
Explanation: The Ti of Ti plasmid refers to as tumor inducing plasmid. It is found in the bacterium Agrobacterium tumefaciens which when infects a plant causes tumor.

4. In which of the plant is the crown gall disease caused?
A. Leaf
B. Root
C. Stem
D. Branches

Answer: C
Explanation: The A. tumefaciens causes a crown gall disease in many dicotyledonous plant species. Crown gall occurs when a wound on the stem allow A. tumefaciens bacteria to cause tumor in the crown region of the stem.

5. The size of the Ti plasmid is around ___________
A. Less than 100 kb
B. More than 200 kb
C. Less than 50 kb
D. More than 75 kb

Answer: B
Explanation: The Ti plasmid is a large plasmid that causes the crown gall disease in plants. The size of the Ti plasmid is more than 200 kb in size that contains the genes involved in the infective process.

6. The part of the bacterial plasmid incorporated in the plant genome includes ___________
A. Virulence region
B. T DNA, 25 base pair repeats
C. Entire plasmid
D. Only T-DNA

Answer: D
Explanation: The remarkable feature of Ti plasmid is that, after infection, a part of the molecule is incorporated into the plant genome. This segment of the Ti plasmid is called the T-DNA or transfer DNA.

7. The size of the T-DNA is around ____________
A. 5 – 10 kb
B. 10 – 20 kb
C. 15 – 30 kb
D. 25 – 30 kb

Answer: C
Explanation: The T-DNA contains the genes required for causing the crown gall disease. It is around 15 – 30 kb in length depending upon the strain of the bacterium.

8. The T-DNA contains how many genes for cancer in the plant?
A. 2
B. 4
C. 6
D. 8

Answer: D
Explanation: The T-DNA contains all the genes that are responsible for the cancerous property in the transformed cells. They are overall 8 in number which resides in the T-DNA that gets incorporated in the plant genome.

9. The sole purpose of the infection of plants by the Ti plasmid is the formation of cancer.
A. True
B. False

Answer: B
Explanation: The formation of cancer is not the sole purpose of infection in the plants. These genes also direct the synthesis of unusual compound called opines, that bacteria use as nutrients.

10. How many process are used to form the chimera Ti plasmid?
A. 1
B. 2
C. 3
D. 4

Answer: B

Energy Engineering Questions and Answers for Freshers focuses on “Feed Water and Steam Generation System, Working of Thermal Power Plant”.

1. What is the storage used to hold the condensed water?
A. Reservoir
B. Tarn
C. Hot well
D. Basin

Answer: C
clarification: Hot well is used for storage of the condensed water in a power plant. A tank or reservoir in which hot water is collected before being recirculated, especially condensed steam about to be returned to a boiler is called Hot well.

2. Feed water from the hot well is supplied to steam generator by using the _________
A. Sewers
B. Cistern
C. Water trough
D. Feed pump
View Answer

Answer: D
clarification: Feed pump is used to pump/supply feed water from hot wall to steam generator. The water may be freshly supplied or returned condensate produced by the boiler. These pumps are positive displacement generator and are of very high capacity.

3. Super heater tubes are made up of what type of material?
A. Copper alloy
B. Carbon steel
C. Titanium alloy
D. Iron

Answer: B
clarification: The steam generated in the boiler is superheated in super heater tubes made of carbon steel for operating at a steam temperature of up to 950°F and carbon molybdenum steel for operating at steam temperature of 1050°F and stainless steel for operating temperature of 1200°F. The tubes of super heater have an outside diameter which ranges from 25mm to 64mm.

4. By what means the power in the steam power plant is developed?
A. Condenser
B. Electric power system
C. Prime mover
D. Economizer

Answer: C
clarification: The prime move s used to develop power in the steam power plant. The water is heated, turns into steam and is made to enter into steam turbine. The steam spins and it drives electric generator connected to it, which generates electricity.

5. Chemicals are added in the feed water.
A. True
B. False
View Answer

Answer: A
clarification: Chemicals are put into feed water through the chemical feed tank to keep water within chemical range. These chemicals are mostly oxygen scavengers and phosphates. The boiler water also has frequent blow downs in order to keep the chloride content down.

6. What is the main objective beyond treating feed water?
A. To remove solid particle
B. To prevent damage by scaling
C. To speed up the steaming process
D. To control conductivity

Answer: B
clarification: The main objective to treat feed water is to prevent damage by scaling and exchange heat without scaling to produce high quality steam. Since a high amount of water is converted into steam back and forth, there is pretty good chance of scale formation in the tubes if the water is not treated.

7. What is the pH value at which the boiler is alkalized?
A. 9.0
B. 5.4
C. 6.9
D. 5.7

Answer: A
clarification: The boiler is alkalized to pH value of 9.0 to reduce oxidization and to support the formation of a stable layer of magnetite on water side surface of the boiler protecting from oxidation. And also oxygen scavengers are used to remove residues of oxides, especially O₂ & CO₂ [oxygen and carbon dioxide] must be removed. Sodium hydroxide or ammonia is used for alkalization of the feed water.

8. What does steam power plant mainly use to generate steam?
A. Boiled water
B. Fresh steam
C. Flue gas
D. Condensed water

Answer: C
clarification: Steam power mainly uses hot products of combustion known as flue gas to generate steam in a boiler. Heat is generated by burning coal, oil or gas. For this purpose boiler furnace is designed for firing coal, air or gas. The flue gas is exhausted via chimney after making maximum utilization of it.

9. What type of steam is produced in the steam boiler?
A. Low pressure steam
B. High pressure steam
C. Saturated steam
D. Unsaturated steam
View Answer

Answer: C
clarification: The boiler is an integral component of steam engine. A boiler incorporates a firebox or furnace in order to burn the fuel and generate heat. The generated heat is transferred to water to make steam. This produced saturated steam at a rate which can vary according to pressure. The saturated steam thus can produced can either be used immediately to produce power via turbine.

10. What is the main purpose of using an economizer in a boiler?
A. To control the process of steam conversion
B. To reduce energy consumption
C. To increase the temperature of boiler
D. To maintain a constant temperature inside a boiler
View Answer

Answer: A
clarification: Economizer in boilers is used to heat fluids, upto a certain degree not beyond the boiling point of that fluid. Economizers are named so because they can make use of enthalpy in fluid stream that are hot, thereby making more useful enthalpy and improving the boiler’s efficiency.

11. In what form is the coal used in boiler?
A. Big chunks.
B. Medium size crushed
C. Powder form
D. Mixed with fluid

Answer: C
clarification: The coal used for boiler is in powder form, in order to increase thermal efficiency. The different types of coal used in boiler are generally bituminous coal, brown coal and peat. Commonly bituminous coal is most preferred boiler fuel since it has volatile matter from 8 to 33% and ash content of 5 to 16 %.

12. Why is air pre-heater used in the boiler?
A. To draw in the atmospheric air
B. To increase thermal efficiency
C. To heat the air to superheated level
D. To heat the air in advance

Answer: B
clarification: the purpose of the air preheater is to recover the heat from the boiler flue gas which increases the thermal efficiency of the boiler by reducing the useful heat lost in the flue gas. As a consequence the flue gases are also conveyed to the flue gas struck at a lower temperature, allowing simplified design of conveyance system and flue gas stack.

13. What is the advantage of condensing the steam?
A. To cool down the steam
B. To discharge the same amount of feed water taken
C. Reduces the amount of pollution
D. Reduces the amount of fresh feed water

Answer: D
clarification: The principle advantage of condensing operation is to reduce the amount of fresh feed water. A condenser is usually installed after the turbine to convert the exhaust steam from the turbine. They convert gaseous steam into liquid state, at a pressure below atmospheric temperature. Condensing of steam turbine below the atmospheric temperature, the steam pressure drops between the inlet and exhaust of turbine is increased, which increases amount of heat available.

14. How is water dispensed over to the turbine blades?
A. Trough
B. Nozzle
C. Hose
D. Pump

Answer: B
clarification: Nozzle is used to dispense the water over to the turbine blades of steam turbine. A nozzle is a duct that increases the velocity of the flowing fluid at the expense of pressure drop. It’s a duct which decreases the velocity of fluid and increases pressure difference.

15. In what aspect does the nozzle make changes?
A. Temperature
B. Volume
C. Pressure
D. Density

Answer: C
clarification: Nozzle makes changes in terms of pressure variation. And rest all factors/terms are unaffected. By decreasing the pressure and increasing the velocity at other end through convergent-divergent nozzle, the required force or pace can be achieved to run the blades of turbine.

 

Energy Engineering Interview Questions and Answers for Experienced people focuses on “Pulverised Mills – 2”.

1. In which mill is the pulverization of coal is made by the impact?
A. Hammer mill
B. Bowl mill
C. Ball mill
D. Ball and race mill

Answer: A
clarification: In the hammer mill the pulverization of coal is made by impact and this is also called as impact mill. The coal in pulverizer remains in suspension during the entire pulverizing process. All the grinding elements and the primary air fan are mounted on a single shaft.

2. What is done in the primary stage of the grinding in impact mill?
A. Coal is reduced to fine granular state
B. Coal is broken down in medium pieces
C. Coal is dried up to remove the moisture content
D. Coal is mixed up with the other state of fuel to improve the combustion efficiency
View Answer

Answer: A
clarification: The primary air fan induces flow of air through the pulverizer carrying the coal to the primary stage of grinding. In the primary stage of grinding, the coal is reduced to fine granular state by impact with a series of hammers and then into the final stage where pulverization is completed by attrition.

3. What is the purpose of rotary scoop shaped rejecter arms in impact mill?
A. To send back the coal back into grinder for second run
B. To throw the large particles back into the grinder
C. To eliminate ash from the pulverizer
D. To eliminate rocks and solid particles that has mixed up with the coal

Answer: B
clarification: The finely pulverized coal in the final stage of grinding is carried with the air to the burner through the rotating scoop rejecter arms which throw the large particles back into the grinding section. The final stage grinding consists of pegs carried on a rotating disk and travelling between stationary pegs.

4. How is pulverization done in bowl mill?
A. By bowl and steel balls
B. By bowl and roller
C. By bowl and impact hammer
D. By bowl and batan

Answer: B
clarification: The bowl mill consists of rollers and power driven bowl in which pulverization takes place as the coal passes in between the sides of the bowl and the rollers. The automatic control charges the supply of coal to the bowl.

5. What does the primary air that is induced by draught does in a bowl mill?
A. Blows away ash
B. Control the flow of coal
C. Provides air for the combustion
D. Draws heated air
View Answer

Answer: D
clarification: The primary air by induced draught fan draws a stream of heated air through the mill, carrying the pulverized coal into a stationary classifier located at the top of pulveriser. The classifier returns the coarse particles of coal to the desired fineness is carried to the burner through the fan.

6. Which force is used to throw away the heavy particles in the bowl mill?
A. Gravity force
B. Centrifugal force
C. Centripetal force
D. Spring force

Answer: B
clarification: The coal pulverized is carried to the burner through the fan. The impurities in the coal containing heavy particles are thrown over side by centrifugal force as these enter the rotating bowl/ the heavy particles thrown out fall into the space below the bowl.

7. On what basis is selection of bowl mill is not done?
A. Total moisture content of coal
B. Volatile matter
C. Ash producing capacity
D. Grindability

Answer: C
clarification: The selection of bowl mill is done on the basis of total moisture content of coal, sulfur and mineral content (used to determine pyrite removal sizing requirement), Grindability(used to select mill size), volatile matter (used to determine the required coal fineness).

8. What is not the cause of mill fire?
A. Hot startup with normal load
B. Pyrite building from pyrite plows failure
C. Accumulation of coal dust in mill devices
D. Localized hot spots from poor primary air flow

Answer: A
clarification: Mill fires are more often caused due to pyrite building, hot startup on heavy load, accumulation of coal dust etc. the cause of fire is also dependent upon coal properties that exceed pulverizing rating.

Energy Engineering Multiple Choice Questions on “Boiler Mounting Accessories – 1”.

1. How many level indicators are there in the water level indicator of a boiler?
A. 1
B. 2
C. 3
D. 4
View Answer

Answer: B
clarification: The function of the water level indicator is to indicate the level of water inside the boiler drum at any given instant. Two water level indicators (one as a standby) are fitted at the front of the boiler drum. The boiler operator keeps track of water level in the drum and operates the feed pump as per the requirement to maintain a constant level of water inside the drum.

2. What is the function of pressure gauge in the boiler?
A. To indicate steam pressure
B. To indicate water pressure
C. To indicate Air pressure
D. To indicate Flue gas pressure

Answer: A
clarification: The function of the pressure gauge is to indicate the steam pressure inside the boiler drum in bar or in Kgf in cm² or in KN/m² in gauge pressure. If the boiler is fitted with a superheater, one more pressure gauge fitted to the superheater header indicates the superheated steam pressure at any given instant.

3. other than Steam stop valve in the boiler which is the other similar type of valve used?
A. Non-reversible valve
B. Transient valve
C. Reversible valve
D. Junction valve

Answer: D
clarification: Stop valve and junction valve are essentially same. Conventionally stop valves are smaller in size whereas, junction valves are larger. When the valve is mounted on the top most portion of the steam drum, normally the valve is called junction valve. If it is connected in the steam pipe to regulate the flow of steam, the valve is known as stop valve.

4. What type valve is a feed check valve of a boiler?
A. One way valve
B. Globe valve
C. Reversible valve
D. Disc check valve

Answer: A
clarification: Feed check valve regulates the flow of feed water under pressure to the boiler drum. It is essentially a one way valve and allows water to flow only in one direction i.e., towards the boiler drum. No water flows back to the boiler drum.

5. What is the function of Blow down valve of a boiler?
A. To remove sludge
B. To build sediments
C. To remove Flue gas
D. To remove ash
View Answer

Answer: A
clarification: Blow down valve is also called as Blow-off-cock. The function of this valve is to remove the sludge or sediments collected at the bottom of the boiler drum from time to time. Whenever boiler cleaning and inspection is due, water inside the tubes and in the boiler drum can be completely drained by operating the blow down valve.

6. What is the function of fusible plug in the boiler?
A. Protect the fire tube
B. To trip on overload
C. To act as a junction switch
D. To maintain pressure
View Answer

Answer: A
clarification: The function of the fusible plug is to protect the fire tube from burning due to excessive heating. This usually happens when the water level inside the drum becomes too low and the shell and crown plate are directly exposed to steam space.

7. What is the function of safety valves in the boiler?
A. To prevent excessive steam pressure
B. To prevent excessive air pressure
C. To prevent water pressure
D. To prevent from rising temperatures

Answer: A
clarification: The function of safety valve is to prevent the excessive steam pressure inside the boiler drum exceeding the design pressure. When the pressure inside the boiler drum exceeds the rated pressure, safety valve automatically opens and discharges the steam to the atmosphere till normal working pressure is retained.

8. How many types of safety valves are used in boiler in practice?
A. 1
B. 2
C. 3
D. 4
View Answer

Answer: B
clarification: Two types of safety valves are used in practice
i) Spring loaded safety valve
ii) Dead weight safety valve

9. What happens due to high temperature of feeds water in the economizer?
A. Fuel consumption increases
B. Fuel mechanical efficiency increases
C. Fuel consumption decreases
D. Fuel mechanical efficiency decreases
View Answer

Answer: C
clarification: Function of the economizer is to recover a portion of heat of the exhaust gases before the flue gases enter the chimney and discharged to the atmosphere. Due to the high temperature of feed water, fuel consumption reduces. This increases the overall efficiency of the boiler.

10. What is the function of superheater in the boiler?
A. Increase the temperature of steam
B. Reheat the steam
C. Superheat the feed water
D. To heat the fuel gas

Answer: A
clarification: Function of the superheater is to increase the temperature of steam above its saturation temperature. As heat contained in unit mass of superheated steam is more than dry saturated or wet steam, it is extensively used in steam power plants.

11. What is the function Air heater in the boiler?
A. Preheat the air before entering the boiler
B. Recover the heat from flue gas
C. Heating of economizer tubes
D. Reheat the gas coming out of economizer

Answer: B
clarification: Function of air preheater is to recover the heat of a portion of exhaust flue gases before the flue gases enter the chimney. It is places along the passage of the exhaust flue gases in between the economizer and the chimney.

12. Tubular air preheater of a boiler is also called as _________
A. recuperative air preheater
B. elliptical air preheater
C. ovoid air preheater
D. squarish air preheater
View Answer

Answer: A
clarification: Tubular air preheater is also called as recuperative air preheater. This type of air preheater is composed of steel tubes through which hot flue gases flow. Air is made to circulate over these steel tubes and thus gains heat.

13. What does regenerative air preheater consists of?
A. Rotor
B. Skewers
C. Propeller
D. Piston
View Answer

Answer: A
clarification: This type of air preheater consists of a rotor which turns about 2 to 3rpm. The rotor is filled with thin corrugated metal elements. Hot gases pass through one half of the heater and air through the other half. As the rotor turns, the heat storage elements transfer the heat absorbed from the hot gases to the incoming air.

14. What is the function of the feed water pump of a boiler?
A. Pump water at high pressure
B. To pump water at lower pressure
C. To pull back the water from boiler
D. To convert steam into water after the boiler process

Answer: A
clarification: Function of feed water pump is to pump water at high pressure to the water space of the boiler drum. There are many types of feed pumps, in which they are mainly classified into rotary and reciprocating pumps.

15. Rotary pumps are driven by _________
A. electric motors
B. batteries
C. diesel engines
D. biogas fuel

Answer: A
clarification: Rotary pumps are driven by electric motors. Water is pumped due to rotary action of the impeller. Rotary pumps are invented by Charles C Barnes. It is a positive displacement pump. The efficiency of these pumps depends on the percentage of slip to the total quantity displaced.

Energy Engineering Multiple Choice Questions on “Nuclear Fission & Nuclear Fusion”.

1. In which of the following process are Neutrons emitted?
A. Inverse beta Decay
B. Nuclear fission
C. Spontaneous Fission
D. Nuclear fusion

Answer: B
clarification: Nuclear fission is the process in which a heavy nucleus is split into two or more lighter nuclei. This result in decrease in mass and consequent exothermic energy and emission of neutrons take place. Two to three neutrons are emitted per nucleuses which are known as fission elements.

2. Heavy nuclei must be such that they can be fissioned by neutrons of an energy such substance are called?
A. Fission fragments
B. Fission Neutrons
C. Fission species
D. Fission elements

Answer: C
clarification: Heavy nuclei must be such that they can be fissioned by neutrons of energy such substance are called Fission species. All fission species should have long half lives so that the rate of decay is not so fast.

3. Why neutrons with lower energy should be capable of causing fission?
A. For faster reaction process
B. For sustained reaction process
C. For Safety purpose
D. In order to not waste the nuclear fuel
View Answer

Answer: B
clarification: Due to collisions with various nuclei, initial high kinetic energy of fission neutron decreases. Thus for a sustained reaction, eve neutrons with lower energy should be capable of causing fission. Only neutrons can result in sustained reaction as two or three neutrons are released for each one absorbed by fission.

4. What happens when a neutron is absorbed by a nucleus of an atom of U²³⁵?
A. Mass number of atom increases
B. One electron is let out
C. U²³⁶ isotope is formed
D. Nucleus becomes unstable

Answer: C
clarification: When a neutron is absorbed by a nucleus of an atom U²³⁵, a U²³⁶ isotope is formed. This isotope is highly unstable which lasts for one millionth of a second and splits into two equal parts releasing energy of 200MeV.

5. Who invented nuclear fission?
A. Rutherford
B. Hans Bethe
C. Otto Hahn
D. Marie Curie

Answer: C
clarification: Nuclear fission of heavy metals was discovered by German Otto Hahn on December 17, 1938 and was explained theoretically by Lise Meitner and her nephew Otto Robert Frisch on 1939. Frisch named Frisch names the process by analogy with biological fission of living cells.

6. Atoms of different chemical elements that have the same number of nucleons are called as?
A. Isobars
B. Isotones
C. Isomers
D. Isotopes

Answer: A
clarification: Atoms of different chemical elements that have the same number of nucleons are called as isobars. The term isobar was suggested by Alfred Walter Stewart in 1918. It is derived from Greek word ‘isos’ meaning EQUAL and ‘baros’ meaning WEIGHT.

7. Most of the energy released in fission process is in process of __________
A. Kinetic Energy
B. Thermal Energy
C. Light Energy
D. Heat Energy

Answer: A
clarification: Most of the energy released is in the form of kinetic energy and is absorbed by fission products. The fission products formed are fission fragments, neutrons and electromagnetic or gamma radiation. As the fragments collide, the kinetic energy is converted into heat energy.

8. Combining of two light nuclei of low mass to produce a heavy nucleus is called ___________
A. Nuclear fusion
B. Nuclear fission
C. Spontaneous fission
D. Double beta decay
View Answer

Answer: A
clarification: Nuclear fusion is the process which involves fusion of two light nuclei of low mass to produce a heavy nucleus which results in decrease of mass and release of enormous amount of energy. All atomic bombs prefer nuclear fission process.

9. What type of Reaction takes place in sun?
A. Nuclear fusion
B. Nuclear fission
C. Spontaneous fission
D. Double beta decay

Answer: A
clarification: Nuclear fusion reaction takes place in sun as well as stars. The process is carried by proton-proton chain. The sun starts with protons, and through a series of steps, turns them into helium. Every second 600 million tons of hydrogen is converted into helium. The reaction releases tremendous amount of heat and energy.

10. How many number of nuclei of hydrogen fuse in a series of reaction involving other particles that continually appear and disappear?
A. 1
B. 2
C. 3
D. 4
View Answer

Answer: D
clarification: Four nuclei of hydrogen fuse in a series of reaction involving other particles that continually appear and disappear such as He3, nitrogen, carbon and other nuclei.
4₁H¹ → ₂He⁴ + 2₊₁e⁰ (Positrons)
Mass decreases to about 0.0276amu releasing 25.7MeV. The heat liberated during this result in temperature of the order of the million degrees and sustains the succeeding reactions.

11. Why is it necessary to accelerate positively charged nuclei to high kinetic energies to cause fusion?
A. To overcome electrical repulsive forces
B. To result in high amount of energy in short period of time
C. To get the isobars and isotopes
D. To get a sustainable reaction

Answer: A
clarification: To cause fusion, it is necessary to accelerate positively charged nuclei to high kinetic energies to overcome electrical repulsive forces. This is done by rising their temperatures to hundreds of millions of degree resulting in plasma.

12. Fusion reactions are called __________
A. Thermonuclear
B. Thermoduric
C. Thermo Uric
D. Compound reactions

Answer: A
clarification: To eradicate repulsive forces temperature of positively charged nuclei is raised to millions of degree resulting in plasma. The plasma should be prevented from contacting the walls of the container confined for a period of time of the order of a second at a minimum density. Fusion reactions are called thermonuclear because of the higher temperature requirement to trigger and sustain the reaction.

13. Which of the following element is readily available in the ordinary water?
A. Cesium
B. Thorium
C. Deuterium
D. Astatine
View Answer

Answer: C
clarification: Deuterium used in fusion reaction is readily available in ordinary water (Out of 6500 molecules). Deuterium is also known as heavy hydrogen. The nucleus of deuterium is called as deuteron, Contains one proton and one neutron.

14. How is tritium made from sea water?
A. By bombarding lithium
B. By bonding with carbon
C. By bombarding Beryllium
D. By reacting with oxygen

Answer: A
clarification: Tritium is made by seawater by bombarding with lithium. Lithium is a chemical element with Atomic number: 3 and Mass number: 6.941 u ± 0.002 u. Because of its relative nuclear instability, lithium is less common in the solar system.