Quiz: Civil Engineering

Exam: UPSSSC-JE

Topic: Hydraulics & Fluid Mechanics

Each question carries 1 mark

Negative marking: 1/3 mark

Time: 10 Minutes

Q1.The relationship between atmospheric pressure (Patm), gauge pressure (Pgauge) and absolute pressure (Pabs) is given by :

(a) Patm = Pabs + Pgauge

(b) Pabs = Patm + Pgauge

(c) Patm = Pabs + Pgauge

(d) none of the above

L1Difficulty 3

QTags Hydraulics & Fluid Mechanics

QCereator Anubhav Gupta

Q2. Wind speed is measured by an instrument

(a) Reflectometer

(b) Planimeter

(c) Anemometer

(d) Speedometer

L1Difficulty 3

QTags Hydraulics & Fluid Mechanics

QCereator Anubhav Gupta

Q3. Viscosity of water in comparison to mercury is :

(a) Higher

(b) Lower

(c) Same

(d) Higher/Lower depending on Temperature

L1Difficulty 3

QTags Hydraulics & Fluid Mechanics

QCereator Anubhav Gupta

Q4. Dynamic viscosity of a fluid with specific gravity 1.3 is measured to be 0.0034 Ns/m² its kinematic viscosity, in m²/sec is :

(a) 2.6 × 10^(–6)

(b) 4.4 × 10^(–6)

(c) 5.8 × 10^(–6)

(d) 7.2 × 10^(–6)

L1Difficulty 3

QTags Hydraulics & Fluid Mechanics

QCereator Anubhav Gupta

Q5. Poise is unit of

(a) (Dyne-sec )/(cm^2 )

(b) (Dyne-cm)/sec〖 〗

(c) (Dyne-cm)/〖sec〗^2

(d) (Dyne-sec )/cm

L1Difficulty 3

QTags Hydraulics & Fluid Mechanics

QCereator Anubhav Gupta

Q6. The depth of centre of Pr. For a vertically immersed surface from the liquid surface given by :

(a) I_G/A_¯X – ¯X

(b) I_G/¯X – A_¯X

(c) A_¯X/I_G + ¯X

(d) I_G/A_¯X + ¯X

L1Difficulty 3

QTags Hydraulics & Fluid Mechanics

QCereator Anubhav Gupta

Q7. Which one of the following pressure unit represents the least pressure?

(a) Millibar

(b) mm of Hg

(c) N/mm²

(d) kgf/cm²

L1Difficulty 3

QTags Hydraulics & Fluid Mechanics

QCereator Anubhav Gupta

Q8. Atmospheric pressure is measured by _____ .

(a) Altimeter

(b) Piezometer

(c) Barometer

(d) Spectrometer

L1Difficulty 3

QTags Hydraulics & Fluid Mechanics

QCereator Anubhav Gupta

Q9.Hydraulic radius is :

(a) (Wetted perimeter)/(Cross-sectional Area)

(b) (Cross-sectional Area)/(Wetted perimeter)

(c) Radius of channel

(d) All of above

L1Difficulty 3

QTags Hydraulics & Fluid Mechanics

QCereator Anubhav Gupta

Q10. Spherical shape of droplets of mercury is due to

(a) high density

(b) high surface tension

(c) high adhesion

(d) Water

L1Difficulty 3

QTags Hydraulics & Fluid Mechanics

QCereator Anubhav Gupta

Solutions

S1. Ans.(b)

Sol: Pabs = Patm + Pgauge

S2. Ans.(c)

S3. Ans.(b)

S4. Ans.(a)

Sol. μ = 0.0034 Ns/m²

G = 1.3

γ = 3

γ = μ/ρ = μ/(Gγ_ω )

⇒ (0.0034 Ns/m^2 )/(1.3×1000 kg/m³)

⇒ 2.6 × 10^(–6) m²/sec.

S5. Ans.(a)

S6. Ans.(d)

Sol. ¯h = (I_G sin²θ)/(A¯X) + ¯X

For vertically θ = 90°

[¯h = (I_G sin²θ)/(A¯X) + ¯X]

S7. Ans.(a)

Sol. 1 millibar = 10^(–3) bar

= 10^(–3) × 10^5 N/m²

= 100 N/m²

1 mm of Hg = (1×13.6×1000×9.81)/1000

= 133.416 N/m²

1 N/mm² = 10^6 N/m²

1 kgf/cm² = (1×9.81 N)/10^(–4) = 9.81 × 10^4 N/m²

S8. Ans.(c)

Sol.

S9. Ans.(b)

Sol.

Hydraulic Radius = (C⁄s Area)/(Wetter Perimeter) ▭(R=A/P)

S10. Ans.(b)

Sol. due to the surface tension is in balance with the internal pressure and the droplet form into sphere which is the shape for minimum surface area.