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Multiple choice question for engineering

Set 1

1. Bending stress in graduated length leaves are more than that in full length leaves.
a) Yes
b) No
c) In some cases
d) Can’t be stated

View Answer

Answer: b [Reason:] Bending stress in full length leaves is around 50% higher than graduated length leaves.

2. Nip is the initial gap between extra full length leaf and the graduated length leaf before the assembly.
a) True
b) False

View Answer

Answer: a [Reason:] Nipping is done to balance the bending stress in the full length leaf and graduated length leaf.

3. Nipping is defined as leaving the gap between full length leaf and graduated length leaf.
a) True
b) False

View Answer

Answer: b [Reason:] Nipping is pre stressing achieved by a difference in radii of curvature.

4. A leaf spring consists of 3 extra full length leaves and 14 graduated length leaves. The maximum force that can act on the spring is 70kN and the distance between eyes of the spring is 1.2m. Width and thickness of the leaves are 100mm and 12mm respectively. If modulus of elasticity is 207000N/mm², calculate the initial nip.
a) 26.8mm
b) 24.9mm
c) 22.5mm
d) 23.1mm

View Answer

Answer: b [Reason:] C=2PLᵌ/Enbtᵌ where L=1.2/2, n=3+14,P=70/2.

5. A leaf spring consists of 3 extra full length leaves and 14 graduated length leaves. The maximum force that can act on the spring is 70kN and the distance between eyes of the spring is 1.2m. Width and thickness of the leaves are 100mm and 12mm respectively. Calculate the initial pre load required to close the nip.
a) 4332.2N
b) 4674.1N
c) 4985.4N
d) Can’t be determined

View Answer

Answer: b [Reason:] P=2x3x14x35000/17(3×3+2×14).

6. Belleville spring can be used in clutch application.
a) True
b) False

View Answer

Answer: a [Reason:] When h/t=2.1, the Belleville spring can be used in clutches.

7. Belleville spring can only produce linear load deflection characteristics.
a) Only linear
b) Linear as well as non linear
c) Non-linear
d) None of the mentioned

View Answer

Answer: b [Reason:] Beliville spring can provide any linear or non-linear load deflection characteristics.

8. When two Belleville sprigs are arranged in series, half deflection is obtained for same force.
a) One fourth deflection
b) Double deflection
c) Four time deflection
d) None of the listed

View Answer

Answer: b [Reason:] Double deflection is obtained.

9. When two Belleville springs are in parallel, half force is obtained for a given deflection.
a) Half force
b) Double force
c) Same force
d) Can’t be determined

View Answer

Answer: b [Reason:] Double force is obtained.

10. Propagation of fatigue failure is always due to compressive stresses.
a) Due to bending
b) Due to tensile
c) Due to fatigue
d) None of the listed

View Answer

Answer: b [Reason:] Propagation is always due to tensile stresses.

11. The strain energy stored in a spiral spring is given by?
a) 12M²L/Ebtᵌ
b) 6M²L/Ebtᵌ
c) 8M²L/Ebtᵌ
d) None of the listed

View Answer

Answer: b [Reason:] U=Mθ/2 where θ=12ML/Ebtᵌ.

Set 2

1. Calculate the angle of wrap if diameter of the two pulleys are 550mm and 300mm. Also the centre distance is 2800mm.
a) 174.8⁰
b) 167.8⁰
c) 159.3⁰
d) None of the mentioned

View Answer

Answer: a [Reason:] ὰ=180 – 2sin¯¹(D-d/2C).

2. Calculate the arc of contact if diameter of the two pulleys are 550mm and 300mm. Also the centre distance is 2800mm.
a) 1.04
b) 1.03
c) 1.01
d) 1.02

View Answer

Answer: d [Reason:] ὰ=180 – 2sin¯¹(D-d/2C). Factor=1+ (1.04-1)(180-174.8)/(180-170).

3. Calculate the belt length if diameter of the two pulleys are 550mm and 300mm. Also the centre distance is 2800mm.
a) 6.5m
b) 4.66m
c) 6.94m
d) 5.26m

View Answer

Answer: c [Reason:] L=2C + π(D+d)/2 + (D-d)²/4C.

4. Crowns are never mounted on the pulley.
a) True
b) False

View Answer

Answer: b [Reason:] Crowns are used to avoid slip in case of misalignment or non-parallelism.

5. In a cast iron pulley minor axis is generally kept in the plane of rotation.
a) True
b) False

View Answer

Answer: b [Reason:] Keeping minor axis in plane of rotation increases the cross section.

6. The number of V belts required for a given application are given by (ignoring correction factor for arc of contact and belt length) Transmitted power/kW rating of single belt x Industrial Service Factor.
a) True
b) False

View Answer

Answer: b [Reason:] It is given by Transmitted power x Industrial Service Factor /kW rating of single belt.

7. The pitch diameter of bigger pulley D in terms of small diameter d is given by
a) dx[speed of smaller pulley/speed of bigger pulley].
b) dx[speed of bigger pulley/speed of smaller pulley].
c) d
d) None of the mentioned

View Answer

Answer: a [Reason:] Product of diameter and speed of pulley is constant.

8. If maximum tension in the belt is 900N and allowable belt load is 500N. Calculate the number of belts required to transmit power.
a) 2
b) 3
c) 4
d) 5

View Answer

Answer: a [Reason:] No of belts=900/500.

9. The belt tension is maximum when velocity of belt is 0.
a) It is max at v=infinity
b) True
c) It is velocity independent
d) It has a constant value

View Answer

Answer: a [Reason:] P₁-mv²/P₂-mv²=e^(fa/sinθ/2). Hence belt tension is maximum when v=0.

10. If belt tension in the two sides is 730N and 140N and belt is moving with a velocity of 10m/s, calculate the power transmitted.
a) 4.5kW
b) 5.9kW
c) 6.2kW
d) None of the mentioned

View Answer

Answer: b [Reason:] Power=(P₁-P₂)xv.

11. If tensions in the belt are P₁ and P₂, then find P₁-mv²/P₂-mv². Contact angle for smaller pulley is 156⁰, Groove angle is 36⁰ and coefficient of friction is 0.2.
a) 6.21
b) 5.83
c) 4.66
d) 5.36

View Answer

Answer: b [Reason:] P₁-mv²/P₂-mv²=e^(fὰ/sinθ/2).

Set 3

1. Which of the following methods is used for determining the decrease in the amount of growth?
a) test done on agar medium plate
b) test done into an agar medium or broth
c) test done by transfering water-soluble substances to sterile media
d) by phenol-coefficient method

View Answer

Answer: b [Reason:] The chemical agent is incorporated into an agar medium or broth, inoculated with the test organism, incubated, and then observed for (i) decrease in the amount of growth or (ii)complete absence of growth.

2. Liquid water-soluble substances appropriately diluted are dispensed into sterile test tubes, to which are added a measured amount of the test organism and then this is transferred into tubes of sterile media.This method helps in determining _____________________
a) whether the inhibitory action is bactericidal
b) whether the inhibitory action is bacteristatic
c) decrease in the amount of growth
d) complete absence of growth

View Answer

Answer: a [Reason:] Liquid water-soluble substances appropriately diluted are dispensed into sterile test tubes, to which are added a measured amount of the test organism.At specified intervals, a transfer is made from this tube into tubes of sterile media that are then incubated and observed for the appearance of growth.It is necessary to ascertain whether the inhibitory action is bactericidal and not bacteriostatic.

3. We observe increased growth in nutrient agar plates as concentration of chemical agent is decreased.
a) True
b) False

View Answer

Answer: a [Reason:] From laboratory evaluation of chemical antimicrobial agents it is found that there is an increased growth in nutrient agar plates as the concentration of chemical agents is reduced.

4. Which of the following acts as a test organism in the procedure of phenol-coefficient method?
a) Escherichia coli
b) Streptococcus faecalis
c) Staphylococcus aureus
d) Lactobacillus

View Answer

Answer: c [Reason:] In the procedure of Phenol-Coefficient method the test organism employed is a specific strain of either Salmonella typhi or Staphylococcus aureus.This procedure is suitable for testing disinfectants miscible with water and exerting antimicrobial action in a manner similar to that of phenol.

5. Which of the following chemical agents lack penetrating power?
a) Phenol
b) Iodine
c) Ethylene oxide
d) Beta-propiolactone

View Answer

Answer: d [Reason:] Beta-propiolactone is a chemical agent which is used for sterilizing instruments and heat-sensitive materials but it lacks the penetrating power.

6. Which of the following agent is used to disinfect skin?
a) Chlorine
b) Formaldehyde
c) Quaternaries
d) Ethylene oxide

View Answer

Answer: c [Reason:] Quaternaries like quaternary ammonium salts are used as a skin disinfectant due to its disinfectant property and detergent property.But it is not sporicidal in nature.

7. Iodine kills the microorganisms by causing denaturation of proteins.
a) True
b) False

View Answer

Answer: b [Reason:] Alcohols, phenols and heavy-metal salts are used to kill the microorganisms by causing denaturation of proteins and reducing the enzyme activity.

8. Which of the following is the mode of action of formaldehyde?
a) interference with glycolysis
b) shows oxidizing property
c) combines with vital nitrogen compounds
d) changes the permeability of cytoplasmic membrane

View Answer

Answer: c [Reason:] Formaldehyde is an extremely reactive chemical.It combines readily with vital organic nitrogen compounds such as proteins and nucleic acids.This interaction accounts for its antimicrobial activity.

9. For sterilization of plastic syringes in hospitals which of the following agents are used?
a) ethylene oxide
b) dyes
c) radiations
d) heavy metals

View Answer

Answer: a [Reason:] Ethylene oxide has an excellent power to penetrate and so it will pass through and sterilize large packages of materials and even plastics such as plastic syringes in hospitals which are sterilized by its vapours.

Set 4

1. A chemical agent that kills the microorganisms and is commonly applied to substances used on inanimate objects are _______________
a) Antiseptics
b) Sanitizer
c) Disinfectants
d) Antibiotics

View Answer

Answer: c [Reason:] Disinfectant is a chemical agent that kills the growing forms but not necessarily the resistant spore forms of disease-producing microorganisms. They are commonly applied to substances used on inanimate objects.

2. An agent that prevents the growth of bacteria are known as __________________
a) Bactericide
b) Bacteriostatic
c) Antimicrobial
d) Antibiotic

View Answer

Answer: b [Reason:] An agent that prevents or inhibits the growth of bacteria are known as bacteriostatic agents and the condition is known as bacteriostasis.

3. For using any chemical agent, we need to increase the temperature of the environment.
a) True
b) False

View Answer

Answer: b [Reason:] One of the characteristics of chemical agents is that they should be toxic to microorganisms at room or body temperature. In using the compound, it should not be necessary to raise the temperature beyond that normally found in the environment where it is to be used.

4. Which of the following is the characteristics of a sanitizer?
a) destroys all microbial forms
b) prevents the growth or action of microorganisms
c) reduces the microbial population to safe levels
d) kills all the bacteria and the bacterial spores

View Answer

Answer: c [Reason:] Sanitizer is an agent that reduces the microbial population to safe levels as prescribed by public health requirements. Usually it is a chemical agent that kills 99.9% of the growing bacteria and are generally applied to inanimate objects.

5. Which of the following is not a chemical agent for microbial control?
a) Radiations
b) Antibiotics
c) Antiseptics
d) Germicide

View Answer

Answer: a [Reason:] Radiations are physical agents for microbial control and includes ionizing as well as non-ionizing radiations to kill the microorganisms.

6. Escherichia coli is much more resistant to cationic disinfectants than Staphylococcus aureus.
a) True
b) False

View Answer

Answer: a [Reason:] Chemical agents are not all equally effective against bacteria,fungi, and other microorganisms. Differences exist between Gram-positive and Gram-negative bacteria: Escherichia coli is much more resistant to cationic disinfectants than Staphylococcus aureus.

7. The process of killing all microorganisms along with their spores is ____________________
a) Disinfection
b) Antisepsis
c) Sanitization
d) Sterilization

View Answer

Answer: d [Reason:] Sterilization is the process of destroying all forms of microbial life.The term sterilization refers to the complete absence or destruction of all microorganisms and should not be used in a relative sense.

8. Which of the following are generally applied on living animal tissues?
a) Antiseptics
b) Disinfectants
c) Preservatives
d) Sanitizer

View Answer

Answer: a [Reason:] Antiseptics are substances that opposes sepsis,i.e., prevents the growth or action of microorganisms either by destroying microorganisms or by inhibiting their growth and metabolism. They are usually applied on living animal tissues.

Set 5

1. The basic requirements of transmitting antennas are:
a) High efficiency
b) Low side lobes
c) Large signal to noise ratio
d) Lone of the mentioned

View Answer

Answer: a [Reason:] The basic requirements of a transmitting antenna are high gain and efficiency while requirements of receiving antennas are low side lobes and large signal to noise to ratio.

2. _________ is a device that converts electrons to photons or vice-versa.
a) Antenna
b) Electron gun
c) Photon amplifier
d) Microwave tube

View Answer

Answer: a [Reason:] Antenna is a device that converts electrons into photons or vice versa. A transmitting antenna converts electrons into photons while a receiving antenna converts photons into electrons.

3. The basic equation of radiation that is applied to any antenna irrespective of the type of the antenna is:
a) iL= Qv
b) iQ = Lv
c) i/L=Q/v
d) None of the mentioned

View Answer

Answer: a [Reason:] Basic equation of radiation is given by iL=Qv. i is the time change in current, l is the length of the current element, q is the charge v is the acceleration of the charge.

4. When the separation between two lines that carry the TEM wave approaches λ the wave tends to be radiated.
a) True
b) False

View Answer

Answer: a [Reason:] When the separation between two lines that chary the TEM wave approaches λ the wave tends to be radiated so that the opened – out line act as an antenna which lunches a free space wave.

5. The number of patterns radiation pattern required to specify the characteristic are :
a) Three
b) Four
c) Two
d) Five

View Answer

Answer: a [Reason:] The three patterns required are, θ component of the electric field as the function of the angles as θ and φ, the φ component of the electric field as the function of the angles θ and φ, the phase of these fields as a functions of the angle φ and θ .

6. The beam width of the antenna pattern measured at half power points is called:
a) Half power beam width
b) Full null beam width
c) Beam width
d) None of the mentioned

View Answer

Answer: a [Reason:] The beam width of an antenna measure at half of the maximum power received by an antenna or the 3 dB beam width of the antenna is termed as half null beam width.

7. An antenna has a field pattern of E (θ) = cos2 θ, θ varies between 0 and 900. Half power beam width of the antenna is:
a) 330
b) 660
c) 12000
d) None of the mentioned

View Answer

Answer: b [Reason:] Half power beam width of the antenna is obtained by equating the field pattern of the antenna to 0.707 (half power point) and finding θ. 2θ gives the value of beam width. Solving the given problem in the same flow, half power beam width of the antenna is 660.

8. An antenna has a field pattern E (θ) =cos θ. cos 2θ. The first null beam width of the antenna is:
a) 450
b) 900
c) 1800
d) 1200

View Answer

Answer: b [Reason:] Half power beam width of the antenna is obtained by equating the field pattern of the antenna to 0.707 (half power point) and finding θ. 2θ gives the value of beam width. Twice the half power beam width gives the first null beam width. With the same steps applied, the half power beam width of the antenna is 450. First null beam width is 900.

9. The solid area through which all the power radiated by the antenna is:
a) Beam area
b) Effective area
c) Aperture area
d) Beam efficiency

View Answer

Answer: a [Reason:] The beam area is the solid angle through which all of the power radiated by the antenna would stream if P (θ, φ) maintained its maximum value over beam area and zero elsewhere. This value is approximately equal to the angles subtended by the half power points of the main lobe in the two principal planes.

10. Power radiated from an antenna per unit solid angle is called radiation intensity.
a) True
b) False

View Answer

Answer: a [Reason:] Power radiated from an antenna per unit solid angle is called radiation intensity. Unit of radiation intensity is watts per steridian or per square degree.