# Quiz: Mechanical Engineering 5th May

Quiz: Mechanical Engineering
Exam: DFCCIL
Topic: Fluid Mechanics/Machines

Each question carries 2 mark
Negative marking: 1/3 mark
Time: 10 Minutes

Q1. Using Blasius equation, the friction factor for turbulent flow through pipes varies as:
(a) Re^(-1)
(b) Re^(-0.5)
(c) Re^(-0.33)
(d) Re^(-0.25)

Q2. In reaction turbine:
(a) kinetic energy is appreciable as the fluid leaves the runner and enters the draft tube
(b) the vanes are partly filled
(c) total energy of fluid is converted to kinetic energy in the runner
(d) it is exposed to the atmosphere

Q3. The unit discharge, Q(u )and unit speed, Nu curve for a turbine is shown in figure. Curve B is for

(a) Francis turbine
(b) Kaplan turbine
(c) Pelton turbine
(d) Propeller turbine

Q4. Kaplan turbine-
(b) is used where high head is available
(c) has inlet adjusted guided vanes

Q5. Bluff body is the body of such a shape that pressure drag as compared to friction drag is
(a) Same
(b) More
(c) Less
(d) Zero

Q6. According to Nikuradse’s the boundary behaves hydrodynamically smooth when
(a) (k/δ)>10
(b) (k/δ)>0.25
(c) (k/δ)<0.25
(d) (k/δ)<8

Q7. The head loss in a sudden expansion from 6 cm diameter pipe to 12 on diameter pipe in terms of velocity v_1 in the smaller diameter pipe is
(a) 3/16.(V_1^2)/2g
(b) 5/16.(V_1^2)/2g
(c) 7/16.(V_1^2)/2g
(d) 9/16.(V_1^2)/2g

Q8. An air vessel is provided at the summit in the syphon in order to
(a) to maintain pressure difference
(b) to increasing discharge
(c) to increase velocity
(d) None of these

Q9. For measuring flow by a venturi-meter, it should be installed in _.
(a) Vertical line
(b) Horizontal line
(c) Inclined line with upward flow
(d) in any direction and in any location

Q10. Which one of the following statements is correct? While using boundary layer equation, Bernoulli’s equation
(a) can be used anywhere
(b) can be used only outside the boundary layer
(c) can be used only inside the boundary layer
(d) cannot be used either inside or outside the boundary layer

Solutions
S1. Ans.(d)
Sol. Friction factor according to Blasius equation,
f=0.316/(Re^(1⁄4) )
f ∝1/(Re^(1⁄4) )
f ∝ Re^((-1)⁄4)
f ∝ Re^(-0.25)

S2. Ans.(a)
Sol. in Case of reaction turbine, Kinetic energy is appreciable as the fluid leaves the runner and enters the draft tube. Draft tube converts this Kinetic energy into useful Pressure energy.

S3. Ans.(a)
Sol. Graph represent the Francis turbine. G.O is Gate open

S4. Ans.(d)

S5. Ans.(b)
Sol. when pressure force is dominated to friction force which both are component of drag force is the condition when submerge body is bluff body.

S6. Ans.(c)
K/δ<0.25=Hydrodynamically smooth. 0.256=Rough
Here, δ = Thickness of laminar. Sublayer
K = Avg height of surface roughness

S7. Ans.(d)
Sol.
h_f=(V_1^2)/2g [1-A_1/A_2 ]^2
A_1=π/4 d_1^2=π/4 (6)^2=9π cm^2
A_2=π/4 d_2^2=π/4 (12)^2=36π cm^2
h_f=(V_1^2)/2g [1-9π/36π]^2=(3/4)^2.(V_1^2)/2g=9/16 .(V_1^2)/2g

S8. Ans.(d)
Sol. Air vessel is provided to maintain the continuity of flow.

S9. Ans.(b)
Sol. Venturi meter has no effect on its reading with its position of placing. It is the device which is independent about its position.

S10. Ans.(b)
Sol. Bernoulli’s equation can be used only outside the boundary layer, Bernoulli’s equation can be applied only for frictionless flow but inside the boundaries there is irrotational flow and in disorganized form

×

Join India's largest learning destination

What You Will get ?

• Daily Quizzes
• Subject-Wise Quizzes
• Current Affairs
• Previous year question papers
• Doubt Solving session

OR

Join India's largest learning destination

What You Will get ?

• Daily Quizzes
• Subject-Wise Quizzes
• Current Affairs
• Previous year question papers
• Doubt Solving session

OR
Join India's largest learning destination

What You Will get ?

• Daily Quizzes
• Subject-Wise Quizzes
• Current Affairs
• Previous year question papers
• Doubt Solving session

Enter the email address associated with your account, and we'll email you an OTP to verify it's you.

Join India's largest learning destination

What You Will get ?

• Daily Quizzes
• Subject-Wise Quizzes
• Current Affairs
• Previous year question papers
• Doubt Solving session

Enter OTP

Please enter the OTP sent to
/6

Did not recive OTP?

Resend in 60s

Join India's largest learning destination

What You Will get ?

• Daily Quizzes
• Subject-Wise Quizzes
• Current Affairs
• Previous year question papers
• Doubt Solving session

Join India's largest learning destination

What You Will get ?

• Daily Quizzes
• Subject-Wise Quizzes
• Current Affairs
• Previous year question papers
• Doubt Solving session

Almost there

+91

Join India's largest learning destination

What You Will get ?

• Daily Quizzes
• Subject-Wise Quizzes
• Current Affairs
• Previous year question papers
• Doubt Solving session

Enter OTP

Please enter the OTP sent to Edit Number

Did not recive OTP?

Resend 60

By skipping this step you will not recieve any free content avalaible on adda247, also you will miss onto notification and job alerts

Are you sure you want to skip this step?

By skipping this step you will not recieve any free content avalaible on adda247, also you will miss onto notification and job alerts

Are you sure you want to skip this step?