# Multiple choice question for engineering

## Set 1

1. Three beakers 1, 2 and 3 of different shapes are kept on a horizontal table and filled with water up to a height h. If the pressure at the base of the beakers are P_{1}, P_{2} and P_{3} respectively, which one of the following will be the relation connecting the three?

a) P_{1} > P_{2} > P_{3}

b) P_{1} < P_{2} < P_{3}

c) P_{1} = P_{2} = P_{3}

d) P_{1} > P_{2} < P_{3}

### View Answer

_{1}= ρgh P

_{2}= ρgh P

_{3}= ρgh Since all the beakers contain water up to to the same height, P

_{1}= P

_{2}= P

_{3}.

2. A beaker is filled with a liquid of specific gravity S = 1:2 as shown. What will be the pressure difference (in kN/m^{2}) between the two points A and B, 30 cm below and 10 cm to the right of point A?

a) 2.5

b) 3.5

c) 4.5

d) 5.5

### View Answer

_{B}= P

_{A}+ ρgh where P

_{B}= Pressure at B, P

_{A}= Pressure at A, ρ = density of the liquid, g = acceleration due to gravity and h = vertical distance separating the two points. PB – PA = 1:2 * 10

^{3}* 9.81 * 0.3 N/m

^{2}= 3.53 kN/m

^{2}

3. The arm of a teapot is 10 cm long and inclined at an angle of 60^{o} to the vertical. The center of the arm base is 2 cm above the base of the beaker. Water is poured into the beaker such that half the arm is filled with it. What will be the pressure at the base of the beaker if the atmospheric pressure is 101.3 kPa?

a) 101.3

b) 101.5

c) 101.7

d) 101.9

### View Answer

^{1}⁄

_{2}* 10 cos 60

^{o}cm = 4:5 cm. Pressure at the base of the beaker = 101.3 + 10

^{3}* 9.81 * 0.045 Pa = 101.3 + 0.44 kPa = 101.74 kPa.

4. A beaker of height 10 cm is half-filled with water (S_{w} = 1) and half-filled with oil (S_{o} = 1). At what distance (in cm) from the base will the pressure be half the pressure at the base of the beaker?

a) 4.375

b) 4.5

c) 5.5

d) 5.625

### View Answer

_{o}* 10

^{3}* 0.05 * g + S

_{w}* 10

^{3}* 0.05 * g = 882.9Pa. Let the required height be h m from the base. If 0.05 ≤ h < 0.1, 800(0.1 – h)g =

^{1}⁄

_{2}* 882.9 Thus, h = 0.04375 (out of the range considered). If 0 < h ≤ 0:05, 800 * 0.05 * g + 10

^{3}* (0.05 – h) * g =

^{1}⁄

_{2}* 882.9 Thus, h = 0.045 (in the range considered). Hence, the correct answer will be 45 cm.

5. A beaker of height 30 cm is filled with water (S_{w} = 1) up to a height of 10 cm. Now oil (S_{o} = 0:9) is poured into the beaker till it is completely filled. At what distance (in cm) from the base will the pressure be one-third the pressure at the base of the beaker?

a) 27.33

b) 19.2

c) 10.8

d) 2.67

### View Answer

_{o}* 10

^{3}* 0.2 * g + S

_{w}* 10

^{3}* 0.1 * g = 2550.6Pa. Let the required height be h m from the base. If 0.1 ≤ h < 0.3, 800(0.3 – h)g =

^{1}⁄

_{3}* 2550.6 Thus, h = 0.192 (in the range considered). Even if there’s no need to check for the other range, it’s shown here for demonstration purpose.If 0 < h ≤ 0.1, 800 * 0.2 * g + 10

^{3}* (0.2 – h) * g =

^{1}⁄

_{3}* 2550.6 Thus, h = 0.2733 (out of the range considered). Hence, the correct answer will be 19.2 cm.

6. An oil tank of height 6 m is half-filled with oil and the air above it exerts a pressure of 200 kPa on the upper surface. The density of oil varies according to the given relation:

What will be the percentage error in the calculation of the pressure at the base of the tank if the density is taken to be a constant equal to 800?

a) 0.01

b) 0.05

c) 0.10

d) 0.15

### View Answer

_{a}and P

_{b}be the pressures at the top and bottom surfaces of the tank, Thus, Pb = 223.5746kPa. If the density is assumed to be constant, Pb = 200 + 800 * 9.81 * 3 * 10

^{3}= 223.544 kPa. Hence, precentage error

7. If a gas X be confined inside a bulb as shown, by what percent will the pressure of the gas be higher or lower than the atmospheric pressure? (Take the atmospheric pressure equal to 101.3 kPa)

a) 4:75% higher

b) 4:75% lower

c) 6:75% higher

d) 6:75% lower

### View Answer

_{a}= P

_{atm}= 101.3 P

_{b}= P

_{a}+ 0.9 * 9.81 * 0.03 = 101.56 P

_{c}= P

_{b}+ 13.6 * 9.81 * 0.04 = 106.9 P

_{d}= P

_{c}– 1 * 9.81 * 0.05 = 106.41 P

_{e}= P

_{d}– 0.9 * 9.81 * 0.04 = 106.1 P

_{X}= P

_{e}= 106.1 Since, P

_{X}> P

_{atm}, the percentage by which the pressure of the gas is higher than the atmospheric pressure will be

8. A tank of height 3 m is completely filled with water. Now two-third of the liquid is taken out and an equal amount of two other immiscible liquids of specific gravities 0.8 and 1.2 are poured into the tank. By what percent will the pressure at the base of the tank change?

a) 0%

b) 5%higher

c) 5%lower

d) 10%higher

### View Answer

9. A beaker of height 15 cm is completely filled with water. Now two-third of the liquid is taken out and an equal amount of two other immiscible liquids of specific gravities 0.8 and 1.2 are poured into the tank. What will be the pressure (in kPa) at a point situated at a height, half the height of the beaker?

a) 588.6

b) 637.65

c) 735.75

d) 833.85

### View Answer

^{3}* 9.81 * 0.05 + 1 * 10

^{3}* 9.81 * 0.025 = 637.65 kPa.

10. A beaker of height h is completely filled with water. Now two-third of the liquid is replaced by another liquid. If the pressure at the base of the beaker doubled, what is the specific gravity of the liquid poured?

a) 0.5

b) 1

c) 2

d) 2.5

### View Answer

_{w}*

^{h}⁄

_{3}* g; Pressure at the base after pouring the second liquid = S

_{w}*

^{h}⁄

_{3}* g + S

_{l}*

^{2h}⁄

_{3}* g, where S

_{w}and S

_{l}are the specific gravities of water and the second liquid.

11. A beaker, partially filled with a liquid is rotated by an angle 30^{o} as shown. If the pressure at point B becomes 12 bar, what will be the height (in cm) of the beaker?

a) 23.5

b) 24.5

c) 26.5

d) 27.5

### View Answer

^{3}* g * h * cos 30

^{o}= 12 * 10

^{3}kPa; h = 24.5 cm.

12. A beaker of height 15 cm is partially filled with a liquid and is rotated by an angle θ as shown.

If the pressure at point B becomes 5 bar, what will be the value of θ?

a) 30^{o}

b) 50^{o}

c) 60^{o}

d) 70^{o}

### View Answer

^{3}* g * 0.15 * cos θ = 5 * 10

^{3}kPa; θ = 70.12

^{o}.

13. A beaker of height 30 cm is partially filled with a liquid and is rotated by an angle θ as shown.

At this point, the pressure at point B is found to be 5 bar. By what angle should θ be increased such that the pressure at B gets halved?

a) 12^{o}

b) 15^{o}

c) 17^{o}

d) 20^{o}

### View Answer

_{1}and θ

_{2}be the angles at which the beaker is inclided for the two cases mentioned. 10

^{3}* 9.81 * 0.15 * cos θ

_{1}= 5 * 100; θ

_{1}= 70.12

^{o}

10^{3} * 9.81 * 0.3 * cos θ_{2} = ^{1}⁄_{2} * 5 * 100; θ_{1} = 85.12^{o}

θ_{2} – θ_{1} = 15^{o}

14. A closed tank (each side of 5 m) is partially filled with fluid as shown. If the pressure of the air above the fluid is 2 bar, find the pressure at the bottom of the tank. Assume the density ρ of the fluid to vary according to the given relation:

a) 766

b) 776

c) 786

d) 796

### View Answer

_{A}= P

_{atm}= 760 P

_{B}= P

_{A}+ 30 P

_{C}= P

_{B}– 50 / 13.6 = 786.32 P

_{X}= P

_{C}= 786.3.

15. For what height of the mercury column will the pressure inside the gas be 40 cm Hg vacuum?

a) 36

b) 40

c) 76

d) 116

### View Answer

_{gas}= P

_{atm}– ρgH Taking gauge pressure in terms of cm of Hg, -40 = 0 – H; H = 40.

## Set 2

1. When is orifice called ‘large orifice’?

a) If the head of liquid is less than 5 times the depth of orifice

b) If the head of liquid is less than 2.5 times the depth of orifice

c) If the head of liquid is less Hence, 4 times the depth of orifice

d) If the head of liquid is less than 1.5 times the depth of orifice

### View Answer

2. In case of any orifice, velocity always remains constant and hence discharge can be calculated.

a) True

b) False

### View Answer

3. Find the discharge through a rectangular orifice 2.2 m wide and 1.3 m deep fitted to a easier tank. The water level in a team is 2.5 m above the top edge of orifice.

a) 13.9 m^{3}/s

b) 11.5 m^{3}/s

c) 16.9 m^{3}/s

d) 8.7 m^{3}/s

### View Answer

^{1.5}– H1

^{1.5}) Here, H1 = 3.8 H2 = 2.5 b = 2.2 Hence, Q = 13.9 m

^{3}/s.

4. Find the discharge through a rectangular orifice 3.2 m wide and 1.7 m deep fitted to a easier tank. The water level in a team is 3.3 m above the top edge of orifice. Take Cd = 0.6

a) 29.4 m^{3}/s

b) 58.5 m^{3}/s

c) 67.9 m^{3}/s

d) 78.7 m^{3}/s

### View Answer

^{1.5}– H1

^{1.5}) Here, H1 = 5 H2 = 3.3 b = 3.2 Hence, Q = 29.4 m

^{3}/s.

5. Find the discharge through totally drowned orifice of width 2.3 m if the difference of water levels on both side of the orifice be 40 cm. The height of water from to and bottom of the orifice are 2.6 m and 2.75 m respectively.

a) .56 m^{3}/s

b) .64 m^{3}/s

c) .75 m^{3}/s

d) .55 m^{3}/s

### View Answer

^{3}/s.

6. Find the discharge through totally drowned orifice of width 3.3 m if the difference of water levels on both side of the orifice be 50 cm. The height of water from to and bottom of the orifice are 2.25 m and 2.67 m respectively.

a) 2.8 m^{3}/s

b) 2.7 m^{3}/s

c) 2.6 m^{3}/s

d) 2.5 m^{3}/s

### View Answer

^{3}/s.

7. A rectangular orifice of 2 m width and 1.2 m deep is fitted in one side of large tank. The easier level on one side of the orifice is 3m above the top edge of the orifice while on the other side of the orifice the water level is 0.5 m below it’s top edge. Calculate discharge if Cd = .64

a) 4.95 m^{3}/s

b) 5.67 m^{3}/s

c) 3.56 m^{3}/s

d) 6.75 m^{3}/s

### View Answer

H = 3.5
Q = 4.94 m^{3}/s.

8. The time taken to empty the tank is independent of Cd but depends only on the height and acceleration due to gravity.

a) True

b) False

### View Answer

9. The discharge rate is independent of the height difference and dependent only on the height.

a) True

b) False

### View Answer

10. In case of submerged orifice the discharge is substantially dependent on temperature of fluid

a) True

b) False

### View Answer

## Set 3

1. Which one of the following is the unit of mass density?

a) kg = m^{3}

b) kg = m^{2}

c) kg = m

d) kg = ms

### View Answer

^{3}.

2. The specific gravity of a liquid has

a) the same unit as that of mass density

b) the same unit as that of weight density

c) the same unit as that of specific volume

d) no unit

### View Answer

3. The specific volume of a liquid is the reciprocal of

a) weight density

b) mass density

c) specific weight

d) specific volume

### View Answer

4. Which one of the following is the unit of specific weight?

a) N = m^{3}

b) N = m^{2}

c) N = m

d) N = ms

### View Answer

^{3}.

5. Which one of the following is the dimension of mass density?

a) [M^{1} L^{-3} T^{0}].

b) [M^{1} L^{3} T^{0}].

c) [M^{0} L^{-3} T^{0}].

d) [M^{0} L^{3} T^{0}].

### View Answer

^{3}] = [ML

^{-3}].

6. Which one of the following is the dimension of specific gravity of a liquid?

a) [M^{1} L^{-3} T^{0}].

b) [M^{1} L^{0} T^{0}].

c) [M^{0} L^{-3} T^{0}].

d) [M^{0} L^{0} T^{0}].

### View Answer

7. Which one of the following is the dimension of specific volume of a liquid?

a) [M^{1} L^{-3} T^{0}].

b) [M^{-1} L^{3} T^{0}].

c) [M^{-1} L^{-3} T^{0}].

d) [M^{0} L^{3} T^{0}].

### View Answer

^{3}]/[M] = [M

^{-1}L

^{3}].

8. Which one of the following is the dimension of specific weight of a liquid?

a) [ML^{-3} T ^{-2}].

b) [ML^{3} T^{-2}].

c) [ML^{-2} T^{-2}].

d) [ML^{2} T^{-2}].

### View Answer

9. Two fluids 1 and 2 have mass densities of p1 and p2 respectively. If p1 > p2, which one of the following expressions will represent the relation between their specific volumes v1 and v2?

a) v1 > v2

b) v1 < v2

c) v1 = v2

d) Cannot be determined due to insufficient information.

### View Answer

10. A beaker is filled with a liquid up to the mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific weight of the liquid will be

a) 6:5 kN = m^{3}

b) 6:6 kN = m^{3}

c) 6:7 kN = m^{3}

d) 6:8 kN = m^{3}

### View Answer

^{-3}N ⁄ m

^{3}= 6:5 kN/m

^{3}.

11. A beaker is filled with a liquid up to the mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific gravity of the liquid will be

a) 0.65

b) 0.66

c) 0.67

d) 0.68

### View Answer

12. A beaker is filled with a liquid up to the mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific volume of the liquid will be

a) 1 l =kg

b) 1:5 l =kg

c) 2 l =kg

d) 2:5 l =kg

### View Answer

## Set 4

1. Two horizontal plates placed 250mm have an oil of viscosity 20 poises. Calculate the shear stress in oil if upper plate is moved with velocity of 1250mm/s.

a) 20 N/m^{2}

b) 2 N/m^{2}

c) 10 N/m^{2}

d) None of the mentioned

### View Answer

^{2}.

2. The kinematic viscosity of oil of specific gravity .8 is .0005 .This oil is used for lubrication of shaft of diameter .4 m and rotates at 190 rpm. Calculate the power lost in the bearing for a sleeve length of 90mm. The thickness of the oil film is 1.5mm.

a) 477.65 Watts

b) 955.31 Watts

c) 238.83 Watts

d) None of the mentioned

### View Answer

3. Find the kinematic viscosity of oil having density 1962 g/m3. the force experienced for area of 20 m2 is 4.904 kN and velocity of gradient at that point is 0.2/s.

a) 0.625

b) 1.25

c) 2.5

d) None of the mentioned

### View Answer

4. The velocity distribution for fluid flow over a flat plate is given by u=2y-6y2 in which u is the velocity in metre per second at a distance of y metre above the plate. Determine the shear stress at y=0.15m.Take dynamic viscosity of fluid as 8.6 poise.

a) 0.172 N/m^{2}

b) 0.344 N/m^{2}

c) 0.086 N/m^{2}

d) None of the mentioned

### View Answer

^{2}.

5. In which types of fluids it is observed that momentum transfer dominates cohesive forces with increase in temperature and hence viscosity increases

a) Gases

b) Liquids

c) Solids

d) None of the mentioned

### View Answer

6. What is the characteristic variation shown by the thixotropic fluids in their shear stress vs. rate of shear strain graph?

a) shear stress increases with increase in rate of shear strain

b) shear stress decreases with increase in rate of shear strain

c) shear stress shows variation only after a definite shear stress is reached

d) shear stress has decreasing constant and then variation relationship with rate of shear strain

### View Answer

7. What happens to viscosity in the case of incompressible fluids as temperature is increased?

a) It remains constant

b) It increases

c) It decreases

d) None of the mentioned

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8. If a fluid, which has a constant specific gravity, is taken to a planet where acceleration due to gravity is 3 times compared to its value on earth, what will happen to its kinematic viscosity.

a) It increases

b) It decreases

c) It remains constant

d) None of the above

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9. In liquids in order to measure the viscosity of fluid experimentally we consider the variation of shear stress with respect to what property?

a) strain

b) shear strain

c) rate of shear strain

d) none of the mentioned

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10. For a compressible fluid the kinematic viscosity is affected by temperature and pressure variation.

a) True

b) False

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## Set 5

1. Find the total pressure on a rectangular plate of dimensions 2×3 m immersed in a fluid of specific gravity 0.65 at a depth of 6 m from the surface.

a) 22.9 N/cm^{2}

b) 45.8 N/cm^{2}

c) 11.5 N/cm^{2}

d) None of the mentioned

### View Answer

^{2}.

2. Find the total pressure on a circular plate of diameter 3 m immersed in a fluid of specific gravity 0.75 at a depth of 5 m from the surface on a planet having acceleration dueto gravity 7 m/s^{2}.

a) 18.5 N/cm^{2}

b) 37 N/cm^{2}

c) 9.25 N/cm^{2}

d) None of the mentioned

### View Answer

^{2}.

3. A rectangular plate surface 3m wide and 5m deep lies in fluid of specific gravity .9 such that its plane makes an angle of 45⁰ with water surface, upper edge 3m below free water surface. Determine the total pressure.

a) 86.5 N/cm^{2}

b) 173 N/cm^{2}

c) 43.25 N/cm^{2}

d) None of the mentioned

### View Answer

^{2}.

4. A rectangular plan surface 5 m wide and 7 m deep lies in water in such a way that its plane makes an angle 60⁰ with the free surface of water. Determine the total pressure force when the upper edge is 3 m below the free surface.

a) 311.15 N/cm^{2}

b) 622.3 N/cm^{2}

c) 155.5 N/cm^{2}

d) None of the mentioned

### View Answer

^{2}.

5. A circular plate 5.0 m diameter is immersed in such a way that its greatest and least depth below the free surface are 3 m and 1 m respectively. determine the position of the centre of pressure.

a) 2.5 m

b) 5 m

c) 4.5 m

d) 6 m

### View Answer

^{4}*sin²23.58/3.142*2.5

^{2}*(1+2.5sin23.58)+*(1+2.5sin23.58) =2.5 m.

6. For an inclined plate the pressure intensity at every point differs.

a) True

b) False

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7. The pressure intensity for a horizontal plate is maximum on the surface of the earth and decreases as we move further away from the surface of the earth either downward or upward.

a) True

b) False

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8. For an inclined plane for which position, maximum total pressure acts on it.

a) Horizontal

b) Vertical

c) Inclined

d) None of the mentioned

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9. The total pressure or pressure intensity is zero for any point on inclined surface in space.

a) True

b) False

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10. In case of spherical bodies with uniform mass distribution, what is the position of center of pressure relative to centre of gravity.

a) Above

b) Below

c) Coincides

d) None of the mentioned