250+ TOP MCQs on Heads in a Turbine and Answers

Hydraulic Machines Multiple Choice Questions on “Heads in a Turbine”.

1. Among the following which turbine requires more head?
a) Pelton Turbine
b) Kaplan Turbine
c) Francis turbine
d) Tube Turbine
Answer: a
Clarification: Except Pelton remaining are reaction turbines, in impulse pressure energy is constant and only available energy is kinetic energy which is directly proportional to head.

2.Total head of turbines is_______
a) Pressure head + Static head
b) Kinetic head + Static head
c) Static head + Pressure head
d) Pressure head + Kinetic head + Static head
Answer: d
Clarification: Generally total is calculated as sum of pressure head, static head and kinetic head.

3. Head under which Kaplan turbine is operated______
a) 10-70 meters
b) 70 -100 meters
c) 100-200 meters
d) Above 200 meters
Answer: a
Clarification: Kaplan turbine is reaction turbine and it operates at low head 10-70 meters and output power is 5-200 MW.

4. Head under which Francis turbine is operated
a) 10-70 meters
b) 70-100 meters
c) 100-200 meters
d) 40 -600 meters
Answer: d
Clarification: Francis turbine is also reaction turbine but pressure energy is less when compared with Kaplan turbine .hence head is between 40 and 600 meters.

5. The turbine is preferred for 0 to 25 m head of water?
a) Pelton wheel
b) Kaplan turbine
c) Tube turbine
d) Francis turbine
Answer: b
Clarification: Kaplan is reaction turbine and its range of operation is between 10-70 meters which has output range between 5-200 MW.

6. Under what head is Pelton turbine operated?
a) 20-50 meters
b) 15-2000 meters
c) 60-200 meters
d) 50-500 meters
Answer: b
Clarification: Pelton turbine is an impulse turbine only energy available is kinetic energy which is proportional to head, hence it requires high head. Theoretically there is no limit to max value of head.

7. _____________ is difference between head race and tail race
a) Gross head
b) Net head
c) Net positive suction head
d) Manometric head
Answer: a
Clarification: Gross head is the difference in elevation of water levels of fore bay and tail race.

8. The head available at inlet of turbine
a) Net positive suction head
b) Gross head
c) Net head
d) Manometric head
Answer: c
Clarification: It is the available effective head used for production. This is also called as static gross head.

9. Head lost due to friction is given by k*f*L*v*v/D*2g where f- friction coefficient, L- length of pen stock, D- diameter of penstock and” k” is constant and its value is ____________
a) 2
b) 3
c) 4
d) 5
Answer: c
Clarification: The constant determined from the given formula is 4.

10. The difference between gross head and friction losses is ____________
a) Net head
b) Gross head
c) Manometric head
d) Net positive suction head
Answer: a
Clarification: Net head is the effective head used to calculate power production. It includes the elimination of frictional losses from the gross head.