D40 MASTER THE DAY

If the gross head is 100 m and net head is 70m, what is the hydraulic efficiency?

• 80%
• 70%

• 60%
• 20%

Answer explanation

Hydraulic efficiency = Net Head / Gross Head = 70/100 = 0.7or 70%.

Ratio of actual energy to maximum possible energy is

• Installed capacity

• Capacity factor

• Overall efficiency
• Head loss

Answer explanation

Capacity factor is the ratio of actual energy produced to the maximum possible energy over a time period.

Which type of turbine is suitable for medium head and discharge?

• Kaplan
• Francis
• Pelton
• Turgo

Answer explanation

Francis turbines are best suited for medium head and medium discharge.

Where is the surge tank located in a hydroelectric system?

• Upstream of turbine
• Inside power house
• At tailrace
• Below draft tube

Answer explanation

Surge tanks are located upstream on the penstock to reduce water hammer.

Which component helps maintain constant pressure before the turbine?

• Forebay
• Surge tank
• Penstock
• Spillway

Answer explanation

Surge tanks absorb sudden changes in pressure.

What is the function of a penstock?

• Store water
• Generate electricity
• Control voltage
• Deliver water under pressure

Answer explanation

Penstocks carry water under pressure to the turbine.

Draft tubes are provided to:

• Reduce cavitation
• Increase velocity
• Generate power
• Transfer energy

Answer explanation

Draft tubes reduce cavitation and recover pressure.

Forebay is located at the:

• Downstream of tailrace
• Just before penstock
• Inside draft tube
• After turbine

Answer explanation

Forebay is a small storage just before the penstock.

Which factor is essential for selecting turbine type?

• Speed
• Load
• Head and discharge
• Reservoir depth

Answer explanation

Turbine selection is mainly based on available head and discharge.

Impulse turbines operate with:

• Water under pressure
• Jet velocity
• Submerged flow
• Radial flow

Answer explanation

Impulse turbines operate using high-speed water jets (jet velocity).