Category: Objective Questions

Bioinformatics Multiple Choice Questions on “Heuristic Database Searching”.

1. The main application of pairwise alignment is retrieving biological sequences in databases based on similarity.
A. True
B. False

Answer: A
Explanation: This process involves submission of a query sequence and performing a pairwise comparison of the query sequence with all individual sequences in a database. Thus, database similarity searching is pairwise alignment on a large scale. This type of searching is one of the most effective ways to assign putative functions to newly determined sequences.

2. Dynamic programming method is the fastest and most practical method.
A. True
B. False

Answer: B
Explanation: Dynamic programming method is slow and impractical to use in most cases. Special search methods are needed to speed up the computational process of sequence comparison.

3. Which of the following is not one of the requirements for implementing algorithms for sequence database searching?
A. Size of the dataset
B. Sensitivity
C. Specificity
D. Speed

Answer: A
Explanation: There are unique requirements for implementing algorithms for sequence database searching out of which, the later three play an important role. However, speed can vary with the size of database. achieving all three at a time is nearly impossible.

4. Sensitivity refers to the ability to find as many correct hits as possible.
A. True
B. False

Answer: A
Explanation: Among the unique requirements for implementing algorithms for sequence database Searching, the first criterion is sensitivity, which refers to the ability to find as many correct hits as possible. It is measured by the extent of inclusion of correctly identified sequence members of the same family. These correct hits are considered ‘true positives’ in the database searching exercise.

5. The specificity refers to the ability to include incorrect hits.
A. True
B. False

Answer: B
Explanation: In heuristic database searching methods, The second requirement criterion is 1 also called specificity, which refers to the ability to exclude incorrect hits. These incorrect hits are unrelated sequences mistakenly identified in database searching and are considered ‘false positives.’

6. In heuristic methods, speed doesn’t vary with the size of database.
A. True
B. False

Answer: B
Explanation: The speed is the time it takes to get results from database searches. Depending on the size of the database, speed sometimes can be a primary concern in the search methods.

7. An increase in sensitivity is associated with _______ in selectivity.
A. no specific change
B. increase
C. decrease
D. exponential increase

Answer: c
Explanation: Ideally, one wants to have the greatest sensitivity, selectivity, and speed in database searches. However, satisfying all three requirements is difficult in reality. What generally happens is that an increase in sensitivity is associated with decrease in selectivity. A very inclusive search tends to include many false positives. Similarly, an improvement in speed often comes at the cost of lowered sensitivity and selectivity. A compromise between the three criteria often has to be made.

8. Which of the following is incorrect?
A. Smith–Waterman algorithm is the fastest
B. Smith–Waterman algorithm is comparatively slower method
C. To speedup up comparison, heuristic methods are used
D. Heuristic algorithms perform faster searches

Answer: A
Explanation: Searching a large database using the dynamic programming methods, such as the Smith–Waterman algorithm, although accurate and reliable, is too slow and impractical when computational resources are limited. To speed up the comparison, heuristic methods have to be used. The heuristic algorithms perform faster searches because they examine only a fraction of the possible alignments examined in regular dynamic programming.

9. Currently, there are two major heuristic algorithms for performing database searches: BLAST and FASTA.
A. True
B. False

Answer: A
Explanation: These methods are not guaranteed to find the optimal alignment or true homologs, but are 50–100 times faster than dynamic programming. The increased computational speed comes at a moderate expense of sensitivity and specificity of the search, which is easily tolerated by working molecular biologists. Both programs can provide a reasonably good indication of sequence similarity by identifying similar sequence segments.

10. Which of the following is incorrect the ‘word’ method?
A. Both BLAST and FASTA use a heuristic word method
B. Word method is used for fast pairwise sequence alignment in BLAST and FASTA
C. The basic assumption is that two related sequences must have at least one word in common
D. Two related sequences must have at zero word in common while assuming

Answer: D
Explanation: This is the third method of pairwise sequence alignment. It works by finding short stretches of identical or nearly identical letters in two sequences. These short strings of characters are called words, which are similar to the windows used in the dot matrix method. The basic assumption is that two related sequences must have at least one word in common. By first identifying word matches, a longer alignment can be obtained by extending similarity regions from the words. Once regions of high sequence similarity are found, adjacent high-scoring regions can be joined into full alignment.

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Genetic Engineering Multiple Choice Questions on “Promoters”.

1. Some vectors carry a mutant form of promoter known as lacUV5 promoter. It carries ______ in the promoter region and _____ the efficiency.
a) point mutations, decreases
b) point mutations, increases
c) frameshift mutations, increases
d) frameshift mutations, increases
Answer: b
Explanation: In some vectors, lacUV5 promoter is present. It is a mutant form and carries point mutations which increase the efficiency.

2. Lambda PL promoter is used in which vectors?
a) Cloning vectors
b) Expression vectors
c) Both cloning and expression vectors
d) Bacteriophage Mu
Answer: b
Explanation: Lambda PL promoters are the promoters for the left region in bacteriophage lambda. It is widely used in expression vectors.

3. The promoter can be controlled by a repressor which is temperature sensitive.
a) True
b) False
Answer: a
Explanation: The promoter is activated at a temperature higher than 30 degrees because at this temperature repressor is inactivated.

4. Choose the correct statement for rifampcin.
a) It inactivates both E. coli polymerase and T7 polymerase
b) It activates both E. coli polymerase and T7 polymerase
c) It inhibits T7 polymerase but doesn’t inhibits E. coli polymerase
d) It inhibits E. coli polymerase but doesn’t inhibits T7 polymerase
Answer: d
Explanation: Rifampcin is added in order to reduce the transcription of other genes. It inhibits the E. coli RNA polymerase but doesn’t inhibit the T7 polymerase.

5. The ______ operon encodes proteins involved in arabinose metabolism.
a) araBCD
b) araABD
c) araBAD
d) araDBA
Answer: c
Explanation: The araBAD operon encodes proteins involved in arabinose metabolism. It is controlled by AraC transcriptional regulator.

6. tac promoter is an example of which type of promoter?
a) hybrid promoter
b) fusion promoter
c) lacZ promoter
d) araBAD promoter
Answer: a
Explanation: Hybrid promoters are those promoters which are produced by two promoters from different sources. Tac promoter is a hybrid promoter produced from trp promoter and lacUV5 promoter.

7. The tac promoter is made by _____ region of trp promoter and _____ region of the lacUV5 promoter.
a) 10, 35
b) 35, 10
c) 10, 10
d) 35, 35
Answer: b
Explanation: It is a hybrid promoter made by 35 regions of trp promoter and 10 regions of the lacUV5 promoter.

8. The tac promoter includes the lac operator and is regulated by a repressor.
a) True
b) False
Answer: a
Explanation: The tac promoter includes the lac operator and is regulated by the repressor. The repressor is to be supplied by the host.

9. Expression of T7 promoter- lac operator hybrid requires ___________
a) T7 RNA polymerase
b) An inducer such as IPTG
c) Both T7 RNA polymerase and inducer such as IPTG
d) T7 DNA polymerase
Answer: c
Explanation: Expression of T7 promoter- lac operator hybrid requires both T7 RNA polymerase and inducer such as IPTG. If inducer is absent levels of expression are very low.

10. When lacUV5 control system is used, addition of IPTG _______ the expression of _________
a) activates, T7 RNA polymerase
b) inactivates, T7 RNA polymerase
c) activates, T7 DNA polymerase
d) inactivates, T7 DNA polymerase
Answer: a
Explanation: When a lacUV5 control system is used, the addition of IPTG activates the expression of T7 RNA polymerase. Thus transcription of sequences under the control of T7 promoter is controlled.

Genetic Engineering Multiple Questions on “Modifications in Cloning Methods, Linkers, Adaptors and Cassettes”.

1. There are various methods to distinguish whether a colony contains a recombinant or not. One such method is __________
a) blue white screening
b) checking whether replication is taking place or not
c) checking the number of copies
d) looking for the multiple cloning site
Answer: a
Explanation: Blue white screening is a method to know whether a colony is having a recombinant or not. It is also known as alpha complementation method. It is based on the lacZ operon. If there is an insert, the colonies are white in colour and if there is no insert, the colonies are blue in colour.

2. At times it is observed that non-recombinant plasmids are more than that of recombinant plasmids. Choose the correct statement in regard to it.
a) It makes easier to get the recombinant plasmids from the mixture
b) The ratio of insert DNA to vector DNA is reduced to get recombinant plasmids
c) Alkaline phosphatase is used to get recombinant plasmids
d) Alkaline phosphatase method is less reliable in comparison to the ratio method
Answer: c
Explanation: Often the recombination plasmids are less in number as compared to non-recombination plasmids. This makes it difficult to get the recombination plasmids from the mixture. In order to overcome this, the ratio of insert DNA to vector DNA is increased. Another more reliable method is to use the alkaline phosphatase method.

3. Alkaline Phosphatase is used at times and the vector is treated with it. Choose the incorrect statement.
a) It removes 5’ terminal phosphate group from nucleic acids
b) The 5’ phosphate group is required for the ligation to take place
c) Two phosphate bonds should be formed for the complete ligation to take place
d) The ligation between vector and insert won’t take place
Answer: d
Explanation: Alkaline phosphatase is used at times and the vector is treated with it. It is responsible for the removal of phosphatase group from the 5’ end. This group is required for the ligation reaction to take place and at each end two phosphates are required. But as the phosphate groups are removed from the vector, its relegation is not possible now. But as the insert is still having a phosphate group, one strand will form the bond and the ligation reaction will take place.

4. What is the correct time for carrying out the alkaline phosphatase treatment?
a) After the cutting of vector has been done
b) Before the insert DNA and the vector are mixed
c) After the cutting of vector has been done but before the insert DNA and vector are mixed
d) After the mixing of insert DNA and vector
Answer: c
Explanation: The alkaline phosphatase treatment is carried out after the cutting of DNA has been done but before the mixing of insert DNA and vector has been done. There should be no traces of the enzyme left after the insert DNA has been added.

5. ccdB gene is used at times. Choose the correct statement with respect to this gene.
a) It is a control of cell birth gene
b) It is activated in complex vectors to increase the fraction of recombinants
c) If intramolecular ligation takes place this protein is released
d) It is often regarded as control of cell death and birth gene
Answer: b
Explanation: It is an approach to increase the fraction of recombinants. There are some genes which are activated on the self ligation of the molecules and are responsible for the death of host molecules. ccdB is control of cell death gene and its protein is responsible for killing the host molecules when intramolecular ligation takes place.

6. When inserting a DNA fragment, it is possible to have two orientations. If the orientation is controlled, this cloning is referred to as __________
a) forced cloning
b) orientation cloning
c) correct cloning
d) restricted cloning
Answer: a
Explanation: It is possible to insert the DNA fragment into two possible orientations. If somehow it is controlled to insert the fragment in a particular orientation, it is known as forced cloning.

7. What happens if insert DNA is cut with two different restriction enzymes at the ends?
a) It is difficult to insert the fragment
b) The insert can be ligated in any orientation
c) The insert can be ligated in one orientation only
d) The amount of product increases
Answer: c
Explanation: If the DNA is cut with two different enzymes at the ends, it is possible to ligate the fragment in only one orientation. It is so because each end would have a unique sequence to ligate.

8. What is the disadvantage of amplification of using PCR over natural cloning?
a) In PCR, there is no proof reading activity
b) In PCR, small fragments can’t be amplified
c) There is an A incorporated in PCR products, which makes cloning difficult
d) PCR takes more time as compared to natural cloning
Answer: a
Explanation: The biggest disadvantage of using PCR amplification over natural cloning is that there is no proof reading activity in the case of PCR. Thus if an error is induced, it is carried forward and is amplified. Also, if large fragments are to be cloned, natural cloning is preferred over PCR. The incorporated A at ends makes the process of cloning of PCR products easier.

9. TA cloning is a method used for cloning of PCR products. Which of the statement is correct with respect to it?
a) It is based on the fact that a T residue is incorporated at the end of the PCR product
b) ‘A’ residue is incorporated into the end of the vector
c) It gives a low yield
d) It is preferred over blunt end ligation
Answer: d
Explanation: TA cloning is a method used for cloning of PCR products. It is based on the fact that A residue is present at the 3’ end of the PCR product and thus now T residue is incorporated at the end of the vector. It is preferred over blunt end ligation.

10. Choose the incorrect statement in respect to topoisomerase I.
a) It is used to cleave only one DNA strand
b) It leaves at the recognition sequence –C/TCCTT- and is covalently attached to one end of the cleaved molecule
c) The supercoiling of the DNA strand is altered and then it is sealed again by the enzyme
d) It is slower than the normal DNA ligase
Answer: d
Explanation: Topoisomerase I is an enzyme used for cleaving of one DNA strand. It leaves at the recognition sequence –C/TCCTT- and is covalently attached to one end of the cleaved molecule. The supercoiling of the DNA strand is altered and then it sealed by the enzyme again. It is usually faster than DNA ligase. Topoisomerase II is used for cleaving both the strands.

11. Linkers are often used in cloning. Choose the incorrect statement for linkers.
a) These are short chemically synthesized molecules that contain a particular restriction enzyme site within the sequence
b) They are blunt ended molecules
c) They are ligated to staggered ended insert molecules by T4 DNA ligase
d) After treatment with enzyme, both the ends of the linker are staggered
Answer: c
Explanation: Linkers are often used in cloning. These are short chemically synthesized molecules that contain a particular restriction enzyme site within the sequence. They are blunt ended molecules and are ligated to the blunt ended insert molecules by T4 DNA ligase. After treatment with the enzyme, both the ends of the linker are staggered.

12. There is no effect if the insert itself contains the restriction site.
a) True
b) False
Answer: b
Explanation: If the insert itself is having a restriction site, the insert itself is cleaved when the restriction enzyme is cleaved along with the linker. To avoid this, the methylation of the site in the insert is done.

13. Choose the correct statement for adaptors.
a) They are blunt ended at both the ends
b) They are single stranded at both the ends
c) They may be single stranded at one end and other end may be blunt
d) They don’t have extra restriction sites within their sequence
Answer: c
Explanation: Adaptors are molecules which are used for cloning. There is no restriction on the type of end they have. Either of the ends can be blunt or staggered. They may also have extra restriction site within the sequence.

14. If linkers are combined with other features such as a selectable marker, it is called as __________
a) cassette
b) modified linker
c) adaptors
d) induced linker
Answer: a
Explanation: If linkers are combined with the features such as antibiotic resistance, these are called as cassette or cloning cartridges. They may also contain gene expressing signals.

Bioinformatics Questions and Answers for Freshers focuses on “Motif and Domain Databases Using Statistical Models”.

1. Which of the following is not an advantage of Statistical models’ methods in analyzing protein motifs?
A. Sequence information is preserved from a multiple sequence alignment and expresses it with probabilistic models
B. Statistical models allow partial matches and compensate for unobserved sequence patterns using pseudo-counts
C. Statistical models have stronger predictive power than the regular expression based approach, even when they are derived from a limited set of sequences
D. The comparative flexibility is less in case of these methods when compared to regular expressions methods

Answer: D
Explanation: The major limitation of regular expressions is that this method does not take into account sequence probability information about the multiple alignment from which it is modeled making them less flexible. If a regular expression is derived from an incomplete sequence set, it has less predictive power because many more sequences with the same type of motifs are not represented. Unlike regular expressions, position-specific scoring matrices (PSSMs), profiles, and HMMs preserve the sequence information from a multiple sequence alignment and express it with probabilistic models.

2. For motif scanning which of the following programs or databases is for regulated sites curated from scientific literature?
A. ENSEMBL
B. ORegAnno
C. MAST
D. Clover

Answer: B
Explanation: Clover identifies overrepresented motifs in protein sequences whereas; MAST allows users to scan different databases for matches to motifs. ENSEMBL is another online genomic sequence repository which also includes online tools for data mining as well as BLAST searches.

3. Which of the following is not an advantageous feature or algorithm of the database PRINTS?
A. This program breaks down a motif into even smaller non-overlapping units called ‘fingerprints’, which are represented by unweighted PSSMs
B. To define a motif, at least a majority of fingerprints are required to match with a query sequence
C. A query that has simultaneous high-scoring matches to a majority of fingerprints belonging to a motif is a good indication of containing the functional motif
D. The difficulty to recognize short motifs when they reach the size of single fingerprints

Answer: D
Explanation: PRINTS is a protein fingerprint database containing ungapped, manually curated alignments corresponding to the most conserved regions among related sequences. The drawbacks of PRINTS are–the difficulty to recognize short motifs when they reach the size of single fingerprints and a relatively small database, which restricts detection of many motifs.

4. In which of the following multipurpose packages Gibbs sampling algorithm is used?
A. Consensus
B. BEST
C. AlignACE
D. PhyloCon

Answer: c
Explanation: The Gibbs sampling algorithm can identify multiple motifs in a sequence in a sequence set using iterative masking procedure. It is used in AlignACE whereas BEST is a suite of four motif discovery tools integrated in a graphical user interface. Also, Consensus program finds motifs in a set of unaligned sequences and PhyloCon builds on this framework by modeling conservation across orthologous genes from multiple species.

5. Which of the following is untrue in case of the database BLOCKS?
A. The alignments are automatically generated using the same data sets used for deriving the BLOSUM matrices
B. The derived ungapped alignments are called ‘blocks’, which are usually longer than motifs, are subsequently converted to PSSMs
C. A weighting scheme and pseudo counts are subsequently applied to the PSSMs to account for underrepresented and unobserved residues in alignments
D. The functional annotation of blocks is not consistent with that for the motifs

Answer: D
Explanation: BLOCKS is a database that uses multiple alignments derived from the most conserved, ungapped regions of homologous protein sequences. Because blocks often encompass motifs, the functional annotation of blocks is thus consistent with that for the motifs. A query sequence can be used to align with pre-computed profiles in the database to select the highest scored matches. Because of the use of the weighting scheme, the signal-to-noise ratio is improved relative to PRINTS.

6. Which of the following is false in case of the database Pfam and its algorithm?
A. Each motif or domain is represented by an HMM profile generated from the seed alignment of a number of conserved homologous proteins
B. Since the probability scoring mechanism is more complex in HMM than in a profile-based approach the use of HMM yields further increases in sensitivity of the database matches
C. Pfam-B only contains sequence families not covered in Pfam
D. The functional annotation of motifs in Pfam-A is often related to that in UNIPROT

Answer: D
Explanation: Pfam is a database with protein domain alignments derived from sequences in SWISSPROT and TrEMBL. The Pfam database is composed of two parts, Pfam-A and Pfam-B. Pfam-A involves manual alignments and Pfam-B, automatic alignment in a way similar to ProDom. The functional annotation of motifs in Pfam-A is often related to that in PROSITE. Because of the automatic nature, Pfam-B has a much larger coverage but is also more error prone because some HMMs are generated from unrelated sequences.

7. Which of the following is false in case of the database SMART and its algorithm?
A. Contains HMM profiles constructed from manually refined protein domain alignments
B. Alignments in the database are built based on tertiary structures whenever available or based on PSI-BLAST profiles
C. Alignments are further checked but not refined by human annotators before HMM profile construction
D. SMART stands for Simple Modular Architecture Research Tool

Answer: c
Explanation: Alignments are further checked and refined by human annotators before HMM profile construction. Protein functions are also manually curated. Thus, the database may be of better quality than Pfam with more extensive functional annotations. Compared to Pfam,
The SMART database contains an independent collection of HMMs, with emphasis on signaling, extracellular, and chromatin-associated motifs and domains. Sequence searching in this database produces a graphical output of domains with well-annotated information with respect to cellular localization, functional sites, super-family, and tertiary structure.

8. Which of the following is false in case of the database InterPro and its algorithm?
A. InterPro is an integrated pattern database designed to unify multiple databases for protein domains and functional sites
B. This database integrates information from PROSITE, Pfam, PRINTS, ProDom, and SMART databases
C. Only overlapping motifs and domains in a protein sequence derived by all five databases are included
D. All the motifs and domains in a protein sequence derived by all five databases are included

Answer: D
Explanation: The only overlapping motifs and domains in a protein sequence derived by all five databases are included in the database. The InterPro entries use a combination of regular expressions, fingerprints, profiles, and HMMs in pattern matching. However, an InterPro search does not obviate the need to search other databases because of its unique criteria of motif inclusion and thus may have lower sensitivity than exhaustive searches in individual databases. A popular feature of this database is a graphical output that summarizes motif matches and has links to more detailed information.

9. Which of the following is false in case of the CDART and its algorithm?
A. CDART is a domain search program that combines the results from RPS-BLAST, SMART, and Pfam
B. The program is now an integral part of the regular BLAST search function
C. CDART is a substitute for individual database searches
D. It stands for Conserved Domain Architecture

Answer: c
Explanation: CDART is a domain search program that combines the results from various database searches. As with InterPro, CDART is not a substitute for individual database searches because it often misses certain features that can be found in SMART and Pfam.

10. Point out the wrong or irrelevant mathematical method in motif analysis.
A. Enumeration
B. Probabilistic Optimization
C. Deterministic Optimization
D. Literature mining

Answer: D
Explanation: All the rest of the options are indeed valid and proven mathematical methods that contain efficient algorithms in finding motifs in protein sequences. Literature mining is not a mathematical algorithm or tool as such to be used in identifying motifs. But it is definitely a part of research when it comes to find a function of various protein sequences.

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Bioprocess Engineering Multiple Choice Questions on “Fluids in Motion”.

1. Which of the following fluid flow can form “eddies”?
A. Streamline flow
B. Laminar flow
C. Turbulent flow
D. Non-turbulent flow

Answer: C
Explanation: The slower the flow the more closely the streamlines represent actual motion. Slow fluid flow is therefore called streamline or laminar flow. In fast motion, fluid particles frequently cross and recross the streamlines. This motion is called turbulent flow and is characterized by formation of eddies.

2. What do you mean by “u” in the following equation of Reynolds number and for what type of conduit is it applicable?
(R_e = frac{Duρ}{mu})

A. Fluid viscosity, Stirred vessel
B. Average linear velocity, Pipe
C. Average linear velocity, Stirred vessel
D. Fluid viscosity, Pipe

3. In smooth pipes, Laminar flow is encountered at what value of Reynolds number?
A. More than 2100
B. 2100-4000
C. More than 4000
D. Less than 2100

Answer: D
Explanation: One of the most significant outcomes of Reynolds’ experiments is that there is a critical Reynolds number which marks the upper boundary for laminar flow in pipes. In smooth pipes, laminar flow is encountered at Reynolds numbers less than 2100. Under normal conditions, flow is turbulent at R_e above about 4000. Between 2100 and 4000 is the transition region where flow may be either laminar or turbulent depending on conditions at the entrance of the pipe and other variables.

4. What do you mean by incompressible flow?
A. Temperature is constant
B. Density is constant
C. Pressure is constant
D. Velocity is constant

Answer: B
Explanation: In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric flow) refers to a flow in which the material density is constant within a fluid parcel an infinitesimal volume that moves with the flow velocity.

5. Is water incompressible?
A. True
B. False

Answer: B
Explanation: An important concept in fluid mechanics is that liquids, like water and oil, cannot be compressed much when you push down on them in an enclosed container. So, liquids are considered to be incompressible fluids.

6. A garden hose of diameter 2 cm is used to fill a 20 liter bucket. If it takes 1 minute to fill the bucket, what is the speed at which water enters the hose?
A. 106.1 cm/s
B. 106 cm/s
C. 106.5 cm/s
D. 106.8 cm/s

Answer: A
Explanation: The cross-sectional area of the hose will be given by:
A₁ = π r² = π (2 cm/2)² = π cm²
To find the velocity, v₁, we use
Flow rate = A₁ v₁ = 20.0 L/min = (frac{20.0 × 10^3 cm^3}{60.0 s})
v₁ = (frac{20.0 × frac{10^3 cm^3}{60.0s}}{pi cm^2})
= 106.1 cm/s

7. Refer to Q6 and estimate a practical joker pinches the open end of the hose down to a diameter of 5 mm, and sprays his neighbor with it. What is the speed at which water comes out of the hose?
A. 1690 cm/s
B. 1660 cm/s
C. 1698 cm/s
D. 1668 cm/s

Answer: C
Explanation: The flow rate (A₁v₁) of the water approaching the constriction must be equal to the flow rate leaving the hose (A₂v₂). This gives:
v₂ = (frac{A_1 v_1}{A_2})
= (frac{(pi)(106.1)}{(pi)(0.5/2)^2})
= 1698 cm/s.

8. Water flows through a rubber hose 2 cm in diameter at a velocity of 4 m/s. What must be the diameter of the nozzle in order that the water emerge at 16 m/s?
A. 0.884 cm
B. 0.891 cm
C. 0.881 cm
D. 0.894 cm

Answer: D
Explanation: The area is proportional to the square of diameter, so:
v₁d₁² = v₂d₂²
d₂² = v₁d₁² / v₂ = (frac{(4 frac{m}{s})(2cm)^2}{(20 cm)^2})
d₂ = 0.894 cm

9. Water flows through a rubber hose 2 cm in diameter at a velocity of 4 m/s. What is the rate of flow rate of flow in m³/min?
A. 0.0754 m³/min
B. 0.0750 m³/min
C. 0.0764 m³/min
D. 0.0760 m³/min

10. Water ideally flows through a pipe of radius 6 centimeters at a rate of 5 meters per second. The pipe then narrows to a radius of 2 centimeters. What is the new velocity of the water?
A. 50 m/s
B. 55 m/s
C. 60 m/s
D. 65 m/s

11. Venturi relation is one of the applications of ___________
A. Light equation
B. Bernoulli’s equation
C. Speed equation
D. Equation of continuity

Answer: B
Explanation: The flow speed of a fluid can be measured using a device such as a Venturi meter or an orifice plate, which can be placed into a pipeline to reduce the diameter of the flow. For a horizontal device, the continuity equation shows that for an incompressible fluid, the reduction in diameter will cause an increase in the fluid flow speed. Subsequently, Bernoulli’s principle then shows that there must be a decrease in the pressure in the reduced diameter region. This phenomenon is known as the Venturi effect.

12. Simplified equation of continuity is represented as _____________
A. A₁V₂ = A₂V₂
B. A₁V₁ = A₁V₂
C. A₂V₁ = A₁V₁
D. A₁V₁ = A₂V₂

Answer: D
Explanation: Continuity uses the conservation of matter to describe the relationship between the velocities of a fluid in different sections of a system. The simple observation that the volume flow rate, Av, must be the same throughout a system provides a relationship between the velocity of the fluid through a pipe and the cross-sectional area. Continuity works in tandem with Bernoulli’s principle in the design and construction of systems of irrigation, plumbing, etc.

13. Relative density of mercury is _____________
A. 13.6
B. 1
C. 1000
D. 9.8

Answer: A
Explanation: Relative density of a substance is the ratio of its density to that of water.ie. So relative density of mercury is 13.6 means that density of mercury is 13.6 times the density of water.

14. The unit of pressure one bar is ___________
A. 1 Pascal
B. 1 kilo Pascal
C. 100 kPascal
D. 1000 kPascal

15. Reynolds number signifies the ratio of ____________
A. inertia forces to gravity forces
B. buoyant forces to inertia forces
C. inertial forces to viscous forces
D. gravity forces top viscous forces

Answer: C
Explanation: The Reynolds number is the ratio of inertial forces to viscous forces within a fluid which is subjected to relative internal movement due to different fluid velocities, in which is known as a boundary layer in the case of a bounding surface such as the interior of a pipe.