Question 1

​In the equation P = rgQH, the _____ measures the height in feet (ft) from which water descends and determines its pressure.
A) ​Q
B) ​g
C) ​H
D) ​ρ

Accepted Answer

In the equation P = rgQH, the letter "H" measures the height in feet (ft) from which water descends and determines its pressure.

Question 2

Impact turbines are used for high-flow facilities and are not common in residential and small-scale commercial systems.

Accepted Answer

Impact turbines, such as Pelton wheels, are actually used for high-head, low-flow applications, making them suitable for small-scale hydroelectric projects, including residential and small-scale commercial systems, where water flow is limited but can be directed to fall from a height.

Question 3

​Which of the following statements is true regarding the environmental impact of large-scale hydroelectric plants?
A) ​The release of water timed to accommodate peak demands in electricity bears a striking resemblance to natural flood cycles.
B) ​Dams can inundate productive land, destroy wildlife habitat, and interrupt fish migration.
C) ​Water released from dams is usually cooler than the undammed river, preventing undue stress on fish and other organisms.
D) ​When dams flood vegetated land,  the resulting decomposition fertilizes the land for crop growth.

Accepted Answer

Large-scale hydroelectric plants require the construction of dams, which can inundate productive land, destroy wildlife habitat, and interrupt fish migration. While hydroelectric power is a renewable energy source, the environmental impacts of large-scale hydroelectric plants should be carefully considered and mitigated. None of the other statements are true regarding the environmental impact of large-scale hydroelectric plants.

Question 4

​Hydroelectric generators cannot be started or stopped quickly.

Accepted Answer

Hydroelectric generators can be started or stopped quickly, allowing them to respond rapidly to changes in demand for electricity.

Question 5

​Hydropower, unlike solar and wind, offers predictable and reliable energy.

Accepted Answer

Hydropower relies on the flow of water, which is generally consistent and predictable, making it a reliable source of renewable energy. In contrast, solar and wind energy are dependent on weather and can vary in their output, making them less predictable.

Question 6

​_____ turbines are not submerged and use nozzles to focus high-pressure jets of water into curved bowls on the rim of a wheel.
A) ​Impact
B) ​Reaction
C) ​Francis
D) ​Kaplan

Accepted Answer

Impact turbines, also known as impulse turbines, operate by directing high-pressure jets of water onto a wheel or turbine blades, which are not submerged. This action turns the wheel, generating power. The use of nozzles to focus the water into high-speed jets is a characteristic feature of impact or impulse turbines.

Question 7

​Which of the following statements is true regarding micro hydro systems?
A) ​Micro hydro systems range in capacity from less than 100 kW to more than 1 million kW.
B) ​The constancy and predictability of hydropower, even if the available resource is small, dramatically improve off-grid systems.
C) ​For off-grid systems, micro hydro is an unpredictable and unstable source of energy.
D) ​Even without stored resources of a reservoir, power produced by micro hydro installations does not vary with the seasonal flow of the water supply.

Accepted Answer

Micro hydro systems are a reliable source of energy for off-grid systems, and the constancy and predictability of hydropower, even if the available resource is small, improve off-grid systems dramatically. Option A is incorrect because micro hydro systems range in capacity from less than 1 kW to 100 kW. Option C is incorrect because micro hydro is generally considered to be a reliable source of energy for off-grid systems. Option D is incorrect because the seasonal flow of water supply affects the power produced by micro hydro installations.

Question 8

​Most commercial power plants use reaction turbines, designing the turbines to permit fish and other small objects to pass through unharmed.

Accepted Answer

This is true. Most modern power plants use reaction turbines that are designed to allow fish and other small objects to safely pass through. This is accomplished through the use of screens, filters, or other barriers that prevent larger objects from damaging the turbines while still allowing water to flow through.

Question 9

​Small-scale hydropower installations that rely on long pipes to convey water to the turbine experience lower efficiencies than fossil fuel and nuclear power plants.

Accepted Answer

The answer of ​Small-scale hydropower installations that rely on long...

Question 10

​The _____ is a channel or pipe that connects the water intake to the turbine and often includes a control gate for regulating flow rate.
A) ​powerhouse
B) ​tailrace
C) ​intake pipe
D) ​penstock

Accepted Answer

The description given matches the definition of a penstock. A powerhouse is where the turbine and generator are located, a tailrace is the channel that carries water away from the turbine, and an intake pipe is just one part of the whole system.

Quiz 9: Hydropower

​In the equation P = rgQH, the _____ measures the height in feet (ft) from which water descends and determines its pressure.

Impact turbines are used for high-flow facilities and are not common in residential and small-scale commercial systems.

​Which of the following statements is true regarding the environmental impact of large-scale hydroelectric plants?

​Hydroelectric generators cannot be started or stopped quickly.

​Hydropower, unlike solar and wind, offers predictable and reliable energy.

​_____ turbines are not submerged and use nozzles to focus high-pressure jets of water into curved bowls on the rim of a wheel.

​Which of the following statements is true regarding micro hydro systems?

​Most commercial power plants use reaction turbines, designing the turbines to permit fish and other small objects to pass through unharmed.

​Small-scale hydropower installations that rely on long pipes to convey water to the turbine experience lower efficiencies than fossil fuel and nuclear power plants.

​The _____ is a channel or pipe that connects the water intake to the turbine and often includes a control gate for regulating flow rate.

In the equation P = rgQH, the _____ measures the height in feet (ft) from which water descends and determines its pressure.

Which of the following statements is true regarding the environmental impact of large-scale hydroelectric plants?

Hydroelectric generators cannot be started or stopped quickly.

Hydropower, unlike solar and wind, offers predictable and reliable energy.

_____ turbines are not submerged and use nozzles to focus high-pressure jets of water into curved bowls on the rim of a wheel.

Which of the following statements is true regarding micro hydro systems?

Most commercial power plants use reaction turbines, designing the turbines to permit fish and other small objects to pass through unharmed.

Small-scale hydropower installations that rely on long pipes to convey water to the turbine experience lower efficiencies than fossil fuel and nuclear power plants.

The _____ is a channel or pipe that connects the water intake to the turbine and often includes a control gate for regulating flow rate.