# Multiple choice question for engineering

## Set 1

1. If there is no exchange of heat between system and surrounding where system comprises of a compressible fluid but the heat is generated due to friction, the process is an adiabatic.

a) True

b) False

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2. For a compressible fluid, if there is no change in specific volume at constant temperature, what type of process it is?

a) Isothermal process

b) Adiabatic Process

c) Polytropic process

d) None of the mentioned

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3. If the fluid is incompressible, do thermodynamic properties play an important role in its behaviour at varying temperature and pressure?

a) Yes

b) No

c) Depends on the fluid

d) None of the mentioned

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4. If for same temperature and pressure change, the value of bulk modulus is compared for isothermal process and adiabatic process, which one would be higher?

a) Isothermal process

b) Adiabatic process

c) Value is constant for both the processes

d) None of the mentioned

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5. The value of gas constant is same for all the gases

a) True

b) False

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6. Calculate the pressure exerted by 9 kg of air at a temperature of 20℃ if the volume is 0.8m3. Assuming ideal gas laws are applicable.

a) 946 kN/m^{2}

b) 1892 kN/m^{2}

c) 1419 kN/m^{2}

d) None of the mentioned

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^{2}.

7. A gas weighs 16 N/m3 at 30℃ and at an absolute pressure of 0.35 N/mm^{2}. Determine the gas constant.

a) 708.23

b) 354.11

c) 531.17

d) 1062.34

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8. A cylinder of 0.8 m3 in volume contains superheated steam at 70℃ and .4 N/m^{2} absolute pressure. The superheated steam is compressed to .3 . Find pressure and temperature.

a) 0.74 N/m^{2}, 422.3℃

b) 1.48 N/m^{2}, 422.3℃

c) 0.74 N/m^{2}, 844.6℃

d) 1.48 N/m^{2}, 844.6℃

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P2=(v1/v2)n *P1 =(0.8/0.3)1.3 * 0.4 ……..(for superheated stream n=1.3) =.74 N/m2 T1=P1v1/nR=422.3℃.

9. Determine the compressibility of an incompressible fluid, if the pressure of the fluid is changed from 70 N/m^{2} to 130 N/m^{2}. The volume of the liquid changes by 0.15 percent.

a) 0.0025 m^{2}/N

b) 0.0050 m^{2}/N

c) 0.0070 m^{2}/N

d) 0.0012 m^{2}/N

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10. What is the variation of cp, cv and k in case of gases when the temperature increases?

a) cp and cv decreases with temperature, and k increases

b) cp and cv increase with temperature, and k decreases

c) cp and cv increase with temperature, and k increases

d) cp and cv decreases with temperature, and k decreases

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## Set 2

1. A solid cylinder of diameter 5.0 m has a height of 6.0 m. Find the meta-centric height of the cylinder if the specific gravity of the material of cylinder 0.45 and it is floating in water with its axis vertical. State whether the equilibrium is stable or unstable.

a) -0.29 m

b) -0.61 m

c) -1.16 m

d) 0.14 m

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2. A solid cylinder of 15 cm diameter and 40 cm long, consists of two parts made of different materials. The first part at the base is 1.5 cm long and of specific gravity=6.5. The other part of the cylinder is made of the material having specific gravity 0.75. State, if the it can float vertically in water.

a) It will float

b) It will not float

c) Data insufficient

d) None of the mentioned

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3. A wooden cylinder of sp.gr. = 0.6 and circular in cross-section is required to float in oil(sp.gr. = 0.90). Find the L/D ratio for the cylinder to float with its longitudinal axis vertical in oil, where L is the height of cylinder and D is its diameter.

a) L/D<9/16

b) L/D<3/4

c) L/D<2/3

d) None of the mentioned

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For stable equilibrium, GM should be positive GM>0 i.e L/D<3/4.

4. A cylinder(uniform density distribution) of radius 3.0 m has a height of 9.0 m. The specific gravity of the material of cylinder 0.85 and it is floating in water with its axis vertical. State whether the equilibrium is stable or unstable.

a) Stable

b) Unstable

c) Insufficient Data

d) None of the mentioned

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5. If the magnitude of dimension of a rectangular wooden block is length>breadth>height, then for it to float on the water, it should be immersed in what manner?

a) It should be immersed vertically such that length is partially immersed

b) It should be immersed horizontally such that breadth is partially immersed

c) It should be immersed such that height is partially immersed

d) None of the mentioned

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6. When body is completely or partially immersed in a fluid, how much its weight be distributed for it to be in stable equilibrium.

a) Around the lower part

b) Around the upper part

c) Is independent of weight distribution

d) None of the mentioned

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7. In unstable equilibrium what is the relation between forces?

a) Buoyancy force= Weight of body

b) Buoyancy force > Weight of body

c) Buoyancy force < Weight of body

d) None of the mentioned

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8. The floating body is said to be in unstable equilibrium if the metacentre is below the centre of gravity.

a) True

b) False

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9. The floating body is said to be in neutraL equilibrium if the metacentre is above the centre of gravity.

a) True

b) False

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10. In stable equilibrium for completely submerged bodies what is the relation between forces?

a) Buoyancy force= Weight of body,the centre of buoyancy is below the centre of gravity.

b) Buoyancy force=Weight of body, the centre of buoyancy is above the centre of gravity.

c) Buoyancy force < Weight of body

d) None of the mentioned

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## Set 3

1. What is the reduction in crest length due to each end contraction?

a) 0.1H

b) 0.2H

c) 0.15H

d) 0.25H

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2. In Francis formula, the effective length is –

a) L-0.2H

b) L-0.4H

c) L-0.3H

d) L-0.1H

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3. In Francis empirical expression for discharge, the relation between head of water and discharge is

a) Q is directly proportional to H

b) Q is directly proportional to H^{1.5}

c) Q is directly proportional to H^{2.5}

d) Q is directly proportional to H^{0.5}

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^{1.5}.

4. In Bazin’s formula, the discharge is inversely proportional to the length of weir.

a) True

b) False

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5. The head of water over a rectangular weir is 38 cm. The length of the crest of the weir end contraction suppressed is 1.3 m. Find the discharge using the Francis formula.

a) 0.56 m^{3}/s

b) 0.75 m^{3}/s

c) 0.85 m^{3}/s

d) 0.69 m^{3}/s

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^{1.5}= 0.56 m

^{3}/s.

6. The head of water over a rectangular weir is 28 cm. The length of the crest of the weir end contraction suppressed is 1.27 m. Find the discharge using the Francis formula.

a) 0.346 m^{3}/s

b) 0.556 m^{3}/s

c) 0.788 m^{3}/s

d) 0.225 m^{3}/s

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^{0.5}* H

^{1.5}m = ⅔ * Cd = 0.405 + 0.003/H = 0.405 + 0.003/0.28 Q = 0.346 m

^{3}/s.

7. The head of water over a rectangular weir is 26 cm. The length of the crest of the weir end contraction suppressed is 1.25 m. Find the discharge using the Francis formula.

a) 0.304 m^{3}/s

b) 0.502 m^{3}/s

c) 0.350 m^{3}/s

d) 0.625 m^{3}/s

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^{1.5}= 0.304 m

^{3}/s.

8. The head of water over a rectangular weir is 28 cm. The length of the crest of the weir end contraction suppressed is 1.27 m. Find the discharge using the Francis formula.

a) 0.346 m^{3}/s

b) 0.556 m^{3}/s

c) 0.788 m^{3}/s

d) 0.225 m^{3}/s

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^{0.5}* H

^{1.5}m = ⅔ * Cd = 0.405 + 0.003/H = 0.405 + 0.003/0.28 Q = 0.346 m

^{3}/s.

9. Find the discharge over a cipolletti weir of length 1.5 m when the head over the weir is 0.85 m. Take Cd = 0.61.

a) 2.12 m^{3}/s

b) 1.25 m^{3}/s

c) 2.5 m^{3}/s

d) 1.5 m^{3}/s

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^{0.5}* H

^{1.5}= 2.12 m

^{3}/s.

10. Find the discharge over a cipolletti weir of length 1.3 m when the head over the weir is 0.65 m. Take Cd = 0.60.

a) 2.12 m^{3}/s

b) 1.21 m^{3}/s

c) 2.5 m^{3}/s

d) 1.5 m^{3}/s

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^{0.5}* H

^{1.5}= 1.21 m

^{3}/s.

## Set 4

1. Find the position of centre of buoyancy for a wooden block of width 3.5 m and depth 1 m, when it floats horizontally in water. The density of wooden block id 850 kg/m3 and its length 7.0 m.

a) 0.95

b) 0.85

c) 1.05

d) 1.65

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^{3}. h=20.825/3.5*7=0.85 m.

2. A stone weighs 450 N in air and 200 N in water. Compute the volume of stone.

a) .025 m^{3}

b) .05 m^{3}

c) .075 m^{3}

d) None of the mentioned

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^{3}.

3. A stone weighs 650 N in air and 275 N in water. Compute its specific gravity.

a) 1.73

b) 2.45

c) 3.46

d) 0.865

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^{3}specific gravity= Density of stone/Density of water=1.73.

4. A body of dimensions 2.7 m * 3.8 m * 2.5 m, weighs 2500 N in water.Find its weight in air.

a) 254.12 kN

b) 508.25 kN

c) 101.65 kN

d) 127.06 kN

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5. Find the density of metallic body which floats at the interface of mercury of sp.gr 13.6 and water such that 40 % of its volume is sub-merged in mercury and 60% in water.

a) 6040 kg/m^{3}

b) 12080 kg/m^{3}

c) 24160 kg/m^{3}

d) 3020 kg/m^{3}

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^{3}.

6. What is the principal cause of action of buoyant force on a body submerged partially or fully in fluid?

a) Displacement of fluid due to submerged body

b) Development of force due to dynamic action

c) Internal shear forces mitigating external forces

d) None of the mentioned

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7. How can relatively denser object be made to float on the less dense fluid?

a) By altering the shape.

b) By altering the forces acting on the object

c) By altering the shear forces acting on the object

d) None of the mentioned

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8. What happens to the buoyant force acting on the airship as it rises in the air?

a) Buoyant force increases

b) Buoyant force decreases

c) Buoyant force remains constant

d) Buoyant force first increases then shows decrease

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9. As a balloon rises in the air its volume increases, at the end it acquires a stable height and cannot rise any further.

a) True

b) False

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10. Submarines use principle of ‘neutral buoyancy’ to go into the water.

a) True

b) False

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## Set 5

1. Find the discharge of water flowing over a rectangular notch of 1.5 m length when the constant head over the notch is 275 mm. Take Cd = .60

a) 400 lit/s

b) 465 lit/s

c) 385 lit/s

d) 575 lit/s

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^{1.5}= .67 * 1.5 * √19.62 * .275

^{1.5}= .385 m

^{3}/min.

2. The head of water over a rectangular notch is 900 mm. The discharge is 300 litres/s. Find the length of the notch, when CD =.62

a) .192 m

b) .250 m

c) .205 m

d) .175 m

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^{ 1.5}) = 1.5 * .3 / (.62 * √19.62 * .9

^{1.5}) = .192 m.

3. Find the discharge of water flowing over a rectangular notch of 1.3 m length when the constant head over the notch is 255 mm. Take Cd = .62

a) 400 lit/s

b) 465 lit/s

c) 385 lit/s

d) 575 lit/s

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^{1.5}= .67 * 1.3 * √19.62 * .255

^{1.5}= .385 m

^{3}/min.

4. The head of water over a rectangular notch is 700 mm. The discharge is 200 litres/s. Find the length of the notch, when CD =.63

a) .125 m

b) .265 m

c) .250 m

d) .200 m

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^{1.5}) = 1.5 * .2 / (.62 * √19.62 * .7

^{1.5}) = .125 m.

5. Find the discharge over triangular notch of angle 50° when the head over the V notch

a) .93 m^{3}/min

b) 1.45 m^{3}/min

c) .88 m^{3}/min

d) .90 m^{3}/min

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^{1.5}* tan(x) Here, x is the angle. = 8/15 * √19.62 * .22

^{1.5}* tan(50) = .93 m

^{3}/min.

6. The expression for discharge for a right angled notch is more complex than rectangular notch.

a) True

b) False

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7. The results of which are more accurate; rectangular notch or triangular weir.

a) Rectangular notch

b) Triangular weir

c) Both are equally accurate

d) Rectangular weir

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8. What is main reading required in calculation for rectangular notch or weir.

a) H

b) x, x is angle

c) L

d) None of the mentioned

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9. We need to obligatorily have ventilation in triangular notch.

a) True

b) False

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10. Rectangular notch may or may not have ventilation.

a) True

b) False