Category: Objective Questions

Molecular Biology Questions on “Methylation of Eukaryotic DNA Controls Gene Expression – 2”.

1. The CpG islands generally consist of how many GC bases?
A. 100
B. Less than 100
C. More than 1000
D. 1000

Answer: D
Explanation: At certain sites, CpG dinucleotide occurs at a higher frequency and is referred to as CpG islands. CpG islands are approximately 1000 bases long and show an elevated G+C base composition.

2. In humans CpG islands are generally located in the ____________
A. Operator region
B. Promoter region
C. Transcript region
D. Terminator region

Answer: B
Explanation: CpG islands are often associated with the transcription start site, that is, the promoter region. About 60% of human genes have CpG islands at their promoter regions.

3. The Intergenic CpGs are more commonly methylated than in the intragenetic region.
A. True
B. False

Answer: A
Explanation: CpG islands in the genome are located in both intragenic and intergenic regions. In vertebrates over 80% of the methylated cytosine residues are found in the intragenetic regions. In contrast CpGs within the CpG islands are generally either not methylated or have relatively low levels of methylation.

4. Major methylation of CpG islands does not include?
A. Operator
B. Terminator
C. Introns
D. Enhancer

Answer: D
Explanation: The methylation of the genome is persistent throughout and is missing only in regions such as CpG islands within the promoter and enhancer regions. Methylation in these two regions may lead to the silencing of the gene itself.

5. De-novo methylation leads to the phenomenon of genetic imprinting in the offspring.
A. True
B. False

Answer: B
Explanation: Maintenance methylation leads to the phenomenon of genetic imprinting in the offspring. This phenomenon controls the expression of certain genes involved in the development of mammalian embryos.

6. Both the imprinted genes inherited from either parent are expressed in an offspring.
A. True
B. False

Answer: B
Explanation: In an offspring only one of the imprinted genes inherited from either parent is expressed. This phenomenon is known as allelic exclusion.

7. The phenomenon of allelic exclusion leads to the inactivation of one allele of a gene. The active allele is known as ____________
A. Homozygote
B. Homolog
C. Hemizygote
D. Hemilog

Answer: C
Explanation: In the phenomenon of allelic exclusion the active allele is known as hemizygote. And the phenomenon that is exhibited by it is known as functional hemizygosity.

8. Gene of which of the following protein/enzyme/hormone is an example of paternal Hemizygote?
A. Igf-1
B. Igf-2
C. β-globin
D. Insulin

Answer: B

Molecular Biology Multiple Choice Questions on “Site-Directed Mutagenesis & Overview of Recombination”.

1. Which of the following properties is improved by site directed mutagenesis?
A. Physical property
B. Chemical property
C. Kinetic property
D. Integrity

Answer: C
Explanation: Site directed mutagenesis is a process used to achieve protein engineering. Protein engineering improves the kinetic property of the protein by altering the amino acid structure and sequence.

2. What is the formula for annealing temperature for polymerase chain reaction primer?
A. Tm = 81.5 + 0.41 (%AT) – (675/N)
B. Tm = 81.5 + 0.41 (%GC. – (675/N)
C. Tm = 81.2 + 0.41 (%GC. – (672/N)
D. Tm = 81.5 + 0.42 (%AT) – (675/N)

Answer: B
Explanation: For calculating the annealing temperature for a PCR primer is Tm = 81.5 + 0.41 (%GC. – (675/N). Here the % of GC is the total amount of G and C present in the oligonucleotide primer and the target of interested and N is the length of the oligonucleotide primer.

3. What is the function of Dpm I endonuclease in Tm method of site directed mutagenesis?
A. Joining of blunt ends
B. Addition of dNTPs
C. Sensitive to cleavage of methylated DNA
D. Breaking of DNA strand

Answer: C
Explanation: In Tm method the template DNA was deprived from an E. coli cell with an intact restriction modification system. This strand is sensitive to restriction by the Dpn I endonuclease.

4. Which phage is used in oligonucleotide directed mutagenesis?
A. M13
B. Cosmid
C. Phagemid
D. λ – phage

Answer: A
Explanation: M13 phage is single stranded phage. It is used for cloning a specific DNA sequence which will be mutated.

5. Write down the name of scientist who has discovered the method of site directed mutagenesis?
A. Bostein Shortle
B. Craik
C. Grait
D. Joller Smith

Answer: D
Explanation: In 1985 Joller Smith discovered site directed mutagenesis technique. By this technique the nucleotide sequence of a cloned DNA fragment may be changed by site directed mutagenesis using synthetic oligonucleotide.

6. Which two genes are absent in the E. coli strain CJ236?
A. dut-/Ung-
B. Rec-/RecB-
C. duB-/Ung-
D. dut-/Umg-

Answer: A
Explanation: CJ236 which lacks functional dut-phase and uracil N-glycosylase. These are used for generating uracilated single stranded DNA.

7. Which polymerase is used in PCR based mutagenesis?
A. Deep vent R polymerase
B. pfu polymerase
C. Taq polymerase
D. DNA polymerase

Answer: B
Explanation: In PCR based mutagenesis pfu polymerase is used. After 12 – 15 cycles of amplification new strands will be generated.

8. Homologous recombination in germ cells occur in the ____________ phase.
A. Leptotene
B. Zygotene
C. Pachytene
D. Diplotene

Answer: C
Explanation: Homologous recombination in germ cells occurs in the pachytene phase of meiosis I. This exchange is classically termed as crossing over and occurs via the formation of a synaptonemal complex between the two homologous chromosomes.

9. The frequency of crossing over between two genes on the same chromosome is independent of their position.
A. True
B. False

Answer: B
Explanation: The frequency of crossing over between two genes on the same chromosome is dependent of their locus. The more distance between the two genes the more will be the probability of recombination.

10. When two genes on a chromosome are inherited without any record of recombination the genes are said to be ____________
A. Silenced
B. Joined
C. Coordinated
D. Linked

Answer: D
Explanation: When two genes on a chromosome is inherited without any record of recombination the genes are said to be linked. This is because they are placed so close together that no recombination is able to take place. The phenomenon is known as linkage.

11. Homologous recombination does not provide ____________
A. Genetic variation
B. Sequence retrieval
C. Restart of stalled replication
D. Random base incorporation

Answer: D
Explanation: The homologous recombination provides three functions:
i) Provides genetic variation
ii) Allows the retrieval of sequences lost through DNA damage
iii) Provides mechanism for restarting stalled or damaged replication forks.

12. Recombination regulates the function of genes.
A. True
B. False

Answer: A
Explanation: Special types of recombination regulate the expression of some genes. For example, by switching specific segments within chromosomes, cells can put otherwise dormant genes into sites where they are expressed.

13. What is strand invasion?
A. Fork collapse
B. Nick in template strand
C. Formation of lesion
D. Complementary strand pairing

Answer: D
Explanation: The pairing between short regions occurs when a single stranded region of DNA originating from one molecule with its complementary strand in the homologous DNA duplex. This event is known as the strand invasion process.

14. What is the holiday junction?
A. The site of strand break
B. The site of heteroduplex DNA formation
C. Formation of a crossing over complex
D. The site of strand invasion

Answer: C

Energy Engineering Interview Questions and Answers for freshers focuses on “Calorific Value of Fuels – 2”.

1. Which is the common method to relate higher calorific value to lower calorific value?
A. HCV = LCV + H_V (n_{H2O, out} / n_{fuel, in})
B. LCV = HCV + H_V (n_{H2O, out} / n_{fuel, in})
C. HCV = LCV + H_V (n_{fuel, in}/ n_{H2O, out})
D. LCV = HCV + H_V (n_{fuel, in}/ n_{H2O, out})

Answer: A
clarification: H_V – heat vaporization of water.
n_{H2O, out} – moles of water vaporized.
n_{fuel, in} – number of moles of fuel combusted.
High calorific value is equal to low calorific value plus, product of heat of vaporization of water and moles of water vaporized by moles of fuel combusted.

2. Based on what basis are fuels compared?
A. Fire point value
B. High calorific value
C. Flash point value
D. Low calorific value

Answer: D
clarification: On basis of low calorific value the fuels are compared. Low calorific value is the amount of heat evolved when a unit weight of fuel is completely burnt and water vapor leaves with combustion products.

3. Which value is determined by bringing all products of combustion back to original pre-combustion temperature?
A. Higher calorific value
B. Low calorific value
C. Flash point value
D. Fire point value
View Answer

Answer: A
clarification: High calorific value is determined, as all fuels contain hydrogen; they produce water vapor during combustion. When the products of combustion containing water vapor are cooled back to initial temperature, then all water vapors formed condense and evolve latent heat. This adds up to the heat liberated by burning the fuel, producing maximum amount of heat per kg of fuel. This heat is known as the higher calorific value of fuel, and it is denoted by HCV.

4. Which calorific value is same as the thermodynamic heat of combustion?
A. Net calorific value
B. Flash point value
C. Gross calorific value
D. Fire point value

Answer: D
clarification: Gross calorific value is as same as the thermodynamic heat of combustion since the enthalpy change for the reaction assumes a common temperature of the compounds before and after combustion, in which case the water produced by combustion is condensed to a liquid, hence yielding its latent heat of vaporization.

5. Which value is determined by subtracting the heat of vaporization of the water from the higher heating value?
A. Gross calorific value
B. Net calorific value
C. Ignition temperature
D. Fire point temperature
View Answer

Answer: B
clarification: Net calorific value determined. In most of the combustion processes, the products of combustion cannot be cooled to its initial temperature. Thus water vapors don’t condense and hence the latent heat of water vapor is lost to the atmosphere. The resultant heat liberated by the fuel which excludes the latent heat of evaporation of water vapors is known as lower calorific value of fuel.

6. Which formula is used to determine higher calorific value of fuel?
A. Rayleigh’s formula
B. Lamme’s equation
C. Dulongs’s formula
D. Cauchy’s formula

Answer: C
clarification: Higher calorific value of the fuel can be determined by using Dulongs’s formula. Let C, H, O and S represent the percentage by weight of carbon, carbon, oxygen and sulfur respectively.
HCV = 1/100 [33900 + 144000(H – (O/8)) + 9295 S] kJ/Kg
This formula gives gross heating value in terms of the weight fractions of carbon, hydrogen, oxygen and sulfur from the ultimate analysis.

7. Lower calorific value can be determined by equation:
A. LCV = HCV – m*2466
B. LCV = HCV + (m/2466)
C. LCV = HCV – (m/2466)
D. LCV = HCV + (m*2466)
View Answer

Answer: A
clarification: Lower calorific value can be determined equation [LCV = HCV – m*2466]. The latent heat lost to the atmosphere depends on evaporation pressure and the amount of water vapors formed. Due to difficulty in measuring the evaporation pressure, it is assumed that evaporation takes place at a saturation temperature of 15°C. The latent heat corresponding to this saturation is 2466 kl/kg.
m = mass of water vapour formed per kg of fuel burnt.

8. Which fuel has higher calorific value among given fuels?
A. Natural gas
B. Gasoline
C. Diesel
D. Fuel oil

Answer: B
clarification: Gasoline also called as petrol, has the highest calorific value. Gasoline is a transparent petroleum derived liquid that is used primarily as a fuel in internal combustion engines. It consists of mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with variety of additives.

9. What is amount of minimum air required per kg of liquid fuel for complete combustion using carbon, oxygen, hydrogen and sulfur?
A. 1/23 [8/3 C + 8(H – (O/8)) + S]
B. 1/100 [8/3 C + 8(H – (O/8)) + S]
C. 1/100 [8/3 C + 8(H – (0/8))]
D. 1/23 [8/3 C + 8(H – (0/8))]

Answer: A
clarification: Let C, H, O and S represent percentage by mass of carbon(C), Hydrogen (H₂), oxygen and sulfur respectively.
The mass of oxygen required for complete combustion of fuel is given by,
= 1/100 [8/3 C + 8H – O + S]
= 1/100 [8/3C + 8(H – (0/8)) + S]
As air contains 23% of oxygen by mass, minimum air required for burning one kg of liquid fuel completely is given by,
Min. air required = 1/100 [8/3 C + 8(H – (O/8)) + S] 100/23
= 1/23 [8/3 C + 8 (H – (O/8)) + S].

10. What is minimum amount of air required per m³ of gaseous fuel for complete combustion?
A. 1/21 [(H₂/2) + (CO/2) + 2CH₄ + 3C₂H₄] m³/m³ of fuel
B. 1/100 [(H₂/2) + (CO/2) + 2CH₄ + 3C₂H₄] m³/m³ of fuel
C. 1/21 [(H₂/2) + (CO/2) + 3C₂H₄] m³/m³ of fuel
D. 1/100 [(H₂/2) + (CO/2) + 3C₂H₄] m³/m³ of fuel

Answer: A
clarification: Volumetric analysis of fuels hydrogen, carbon monoxide, methane, ethane, carbon dioxide and nitrogen is done and required minimum amount of oxygen is found for one m³ of gaseous fuel:
O₂ required/m³ of fuel = 1/100[(H₂/2) + (CO/2) + 2CH₄ + 3C₂H₄] m³
As atmospheric air contains 21% of O₂ by volume, minimum air required t burn one m³ of gaseous fuel is given by,
Minimum volume of air required (cm³/m³ of fuel):
= 1/100 [(H₂/2) + (CO/2) + 2CH₄ + 3C₂H₄] 100/21
= 1/21 [(H₂/2) + (CO/2) + 2CH₄ + 3C₂H₄] m³/m³ of fuel.

Energy Engineering Multiple Choice Questions on “Function of Boilers”.

1. What is the function of boiler?
A. To burn the fuel in a confined closed system with the supply of air
B. To generate steam at varying pressure
C. To generate steam at constant pressure
D. To produce flue gases by burning fuel at a given pressure
View Answer

Answer: C
clarification: Function of boiler is to generate steam at constant pressure as per the process requirement. The steam generated may be nearly dry saturated or superheated steam. Constant pressure in the boiler is maintained by generating the steam equal to the steam flowing out of the boiler.

2. Why single boiler unit per turbine is equipped commonly?
A. For better turbine control
B. To deduce the costs
C. For overcoming losses of power
D. To improve the efficiency

Answer: A
clarification: In modern power plants it is very common to use a single boiler unit per turbine. This leads to simpler piping systems and relatively easier boiler and better boiler control. And also operating is easier when the connection is made in this type.

3. What is the critical average pressure at which the single boiler unit per turbines is designed to handle?
A. 150 bar
B. 220 bar
C. 740 bar
D. 575 bar

Answer: B
clarification: Single boiler per unit turbines is designed to operate at average critical temperature of 220bar. If the boilers are designed to operate above or below the critical pressure, than they are known as super critical boilers are once through boilers. If the boilers are designed to operate below the critical pressure than they are known as sub critical or drum boilers.

4. How can be the plant efficiency of steam power plant is increased?
A. By using high pressure and high temperature steam
B. By equipping ash and flue gas clearance system
C. By maintaining the boiler on daily basis by cleaning the soot and combustion products
D. By using better and efficient type of fuel for combustion

Answer: A
clarification: The plant efficiency can be increased by using high pressure and high temperature steam. This also reduces the cost of electricity production. The development of newer materials permitted the use of higher operating pressure and temperature of the boiler.

5. Which type of boilers is preferred cost wise when the boilers are required to raise less than 30 tonnes of steam?
A. Flued boiler
B. Cornish boiler
C. Butterley boiler
D. Shell boiler

Answer: D
clarification: The use of shell boilers are considered to be cheaper when the boilers are required to raise less than 30 tonnes of steam per hour and at pressures 30bar. Above these limits, i.e. for high pressure and high output, water tube boilers are preferred.

6. What is the temperature at which the steam boilers are capable to withstand?
A. 200^oC
B. 280^oC
C. 540^oC
D. 358^oC

Answer: C
clarification: The modern high pressure boilers have steam capacities of 30 to 650 tonnes/hour and with pressure of upto 160 bar & maximum steam temperature of about 540^oC. Also the furnace shape is not limited to cylindrical form; hence furnace shape can be changed to suit wide range of situations.

7. The _________ may have water circulation either by natural means due to difference in density or by external means.
A. Piping
B. Tubes
C. Furnace
D. Boiler

Answer: D
clarification: The boiler may have a water circulation either by natural means due to difference in density or by external means (forced circulation). All modern high pressure boiler plants use a pump to force the water to circulate through the boiler plant. The use of natural circulation is limited to the subcritical boilers.

8. What increases as steam pressure increases inside a boiler?
A. Force
B. Density
C. Rate of steam conversion
D. Viscosity

Answer: B
clarification: As the steam pressure increases, its density also increases while the corresponding increase in temperature causes density of water to decrease. This makes the pressure difference causing water flow to decrease.

9. What is needed to be increased to increase the heat transfer rate in the boiler?
A. Gas velocities
B. Fuel input
C. Water velocities
D. Air supply

Answer: C
clarification: Water velocity is required to be increased rather than gas velocities to increase the rate of heat transfer rate in the boiler, because a considerable increase in pressure is more easily produced with water than with gas. Hence, for a given output in boiler, smaller diameter tube may be used.

10. In what is water in high pressure boiler circulated through?
A. Conduits
B. Cove
C. Channel
D. Tubes
View Answer

Answer: D
clarification: In high pressure boilers, water is circulated through the tubes. If the flow of water takes place through one continuous tube, there is a large resistance due to friction and also pressure drop will be more. If the flow is arranged through a parallel system of tubing i.e., through several sets of tubes which are arranged parallel pressure loss will be reduced. This also provides better control over the steam quality.

Energy Engineering Multiple Choice Questions on “Hydrology – 1”.

1. How does Hydro power plays important in development of a country?
A. Shows the amount of water power in a country
B. Providing abundant amount of power
C. Providing power at cheap rate
D. Power production by hydro power plant is easier
View Answer

Answer: C
clarification: In the development of a country the hydro power plays a very important role because it provides power at cheapest rates. No raw material is required for the production of power from hydro power plant.

2. How much of the total amount of power developed world wide consists of hydro power plant?
A. 10%
B. 20%
C. 30%
D. 40%
View Answer

Answer: B
clarification: Nearly 20% of the total world’s power is generated using hydro power plants. To countries in the world 90% of the nation’s power requirement is met by hydro power. When compared country wise this amount is very high.

3. Which two countries have vast hydro resources?
A. Hungary and Luxemburg
B. India and china
C. Russia and Nepal
D. Japan and Georgia
View Answer

Answer: C
clarification: Russia and Nepal have vast hydro resources that are to be harnessed. As per the estimation of world power organization, the world hydro potential is roughly 5000GW whereas only 4% of it (200GW) is presently developed.

4. What type of energy does rain falling holds relative to the oceans?
A. Potential energy
B. Kinematic energy
C. Electrical energy
D. Motion energy

Answer: A
clarification: Rain falling on earth surface has potential energy relative to oceans towards which it flows. This energy can be converted into shaft work by hydraulic prime mover and finally into electrical energy. The conversion of this energy takes time.

5. The shaft power developed by the water passing through the prime mover is given by _______
A. P = (frac{mgH}{1000}) × n_o^.
B. P = (frac{mgH}{10}) × n_o^.
C. P = (frac{mgH}{100}) × n_o^.
D. P = (frac{mgH}{n_{o^.}}) × 1000

6. On what does generation of Hydro power depends?
A. Quantity of water available
B. On capacity of turbine
C. Height of head
D. Storage capacity

Answer: A
clarification: Generation of power depends on the quantity of water available. The available head depends upon the selection of site for hydraulic power plant. The site of the power plant is always selected for the highest available head when other things are in favor of site selection.

7. On what does the Quantity of water available at selected site depends?
A. Temperature at the selected site
B. Humidity at selected site
C. Vegetation of the area
D. Hydrological cycle of area

Answer: D
clarification: The quantity of water available at the selected site depends upon the hydrological cycle of nature. The quantity of water available can be determined from the study of rainfall and run off in the area.

8. Capacity of hydraulic plant is dependent on __________
A. Minimum quantity of water available
B. Vegetation of the selected area
C. Maximum quantity of water available
D. Available head
View Answer

Answer: A
clarification: As the availability of water depends on natural phenomenon of rain, the maximum capacity of hydraulic generating plant is usually fixed on the basis of minimum quantity of water available at selected site.

9. What are used to store water during peak periods?
A. Storage drums
B. Canals
C. Sews
D. Storage Reservoirs
View Answer

Answer: D
clarification: The capacity of the hydraulic plant is done on the basis of minimum quantity available. Usually storage reservoirs are constructed for such plants in order to store the water during peak periods of runoff and supply the same during off peak periods of runoff.

10. The evaporation of water from the surfaces and its precipitation is known as ___________
A. Science
B. Infiltration
C. Hydrological cycle
D. Vegetation

Answer: C
clarification: It’s the science which deals with rainfall and runoff. The evaporation of the water from the surfaces of river and oceans and its precipitation on the earth is known as hydrological cycle. This happens in a particular amount of period.

Energy Engineering Multiple Choice Questions on “Flat Plate Collectors”.

1. To how many types are flat plate collectors divided depending on type of heat transfer fluid?
A. 2
B. 3
C. 4
D. 5

Answer: A
clarification: Based on the type of heat transfer fluid, flat plate collectors are divided into two types, they are Liquid Heating Collectors and Air or gas heating collectors. And also happens that all other types of collectors come under these two types.

2. For what purpose are Gas heating collectors used?
A. To trap solar radiance
B. To act as a medium to help in conversion of sunlight to electrical energy
C. Employed as solar air heaters
D. They act as alternate panels in case of failure

Answer: C
clarification: Air or Gas heating collectors are employed as solar air heaters. Solar air heater is a type of system driving outdoor air through a sealed, sun heated collector mounted on an exterior wall or roof, returning the warmed air back to the living space.

3. Liquid heating collectors are mainly used for _________
A. heating water
B. generating electricity
C. cooking
D. trapping sunlight
View Answer

Answer: A
clarification: Liquid heating collectors are mainly used for heating water. A liquid based solar collector is a solar collector that uses sunlight to heat a liquid that is circulating in a solar loop. The fluid in the solar loop may be water, an anti freeze mixture or thermal oil.

4. _______ is a glazing which limits the radiation and convection heat losses.
A. Absorber plate
B. Selective surface
C. Insulation
D. Transparent cover

Answer: D
clarification: A transparent cover is glazing which limits the radiation and heat convection losses. It includes one or more sheets of glass or radiation transmitting plastic film or sheet. The glass itself is always a single pane adding to adding the second reduces the collector efficiency.

5. What are provided to minimize heat loss?
A. Absorber plate
B. Surface plate
C. Insulation
D. Casing
View Answer

Answer: C
clarification: Insulation is provided at the back and sides to minimize heat losses. Fiber glass or styro-foam is used for this purpose. And also most modern collectors use standard insulators such as polyurethane or polyisocynurate.

6. Which part of flat plate collectors is coated in black?
A. Transparent cover
B. Absorber plate
C. Insulation
D. Fins

Answer: B
clarification: Absorber plate is usually metallic or coated in black surface which is used for absorbing radiation energy. The absorber plate’s coating directly affects how efficient the collector is. Coatings always have two rating figures: how much they absorb and how much they emit.

7. The frame which contains all the parts is called __________
A. box
B. plate
C. enclose
D. container

Answer: D
clarification: Container is used to enclose the other components to protect them from weather. These containers are made of extruded aluminum which can be quite heavy and thick for heavy duty collectors. There are some collectors which are enclosed by fiber glass too.

8. In which collector does air flow without any obstruction?
A. Porous absorber plate
B. Non-porous absorber plate
C. Over lapped glass absorber
D. Finned absorber

Answer: B
clarification: In a simple flat plate air collector, commonly known as non-porous absorbers, the air stream flow through the absorber plate without any obstruction. An analysis of black painted solar air collectors in conventional design in which the air flows below the absorber plate has been made.

9. In which absorber matrix material is arranged and the back absorber plate is eliminated?
A. Porous absorber plate
B. Non-porous absorber plate
C. Over lapped glass absorber
D. Finned absorber

Answer: A
clarification: In the porous bed air heater, the matrix material is arranged and the back absorber plate is eliminated. A single glazed porous bed collector with a reflecting honey comb, extending above the porous to just under the glass cover have theoretically examined.

10. Which type of absorber increases the heat transfer area over a simple flat plate absorber of the same capacity?
A. Porous absorber plate
B. Non-porous absorber plate
C. Over lapped glass absorber
D. Finned absorber

Answer: D
clarification: The finned plate absorber increases the heat transfer area over a simple flat absorber of same capacity. A good design of a finned absorber can increase the heat transfer rate. The temperature difference between the absorber plate and air is very low.

11. In which type of absorber plate is the overall flow direction is along the absorber glass plate?
A. Overlapped glass absorber
B. Finned absorber
C. Non-porous absorber plate
D. Porous absorber plate
View Answer

Answer: A
clarification: In overlapped absorber plate, overall flow direction is along the absorber glass plate instead of being across the matrix. Plate and air stream temperature increase gradually along the collector length and across from top to bottom.

12. How is heat loss over come in liquid plate collectors?
A. By insulation
B. By casing
C. By the transparent cover
D. From provided tubes

Answer: A
clarification: Heat is transferred from the absorber plate to a point of use by the circulating fluid via water across the solar heated surface. The heat loss from the surface is prevented by placing thermal insulation of 5 to 10cm thickness behind the absorber plate.