Chapter 6 Multiple Choice Questions

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1) The percentage of global electricity production due to hydropower in 2018 was…

1.2%. correct incorrect

5%. correct incorrect

12%. correct incorrect

16%. correct incorrect

21%. correct incorrect

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2) The power per metre width in a typical ocean wave is about…

1 kW m^-1. correct incorrect

10 kW m^-1. correct incorrect

50 kW m^-1. correct incorrect

200 kW m^-1. correct incorrect

400 kW m^-1. correct incorrect

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3) Which one of the following statements is correct about a Fourneyron turbine?

It employs fixed guide vanes and fixed runner blades. correct incorrect

It employs fixed guide vanes and moving runner blades. correct incorrect

It employs moving guide vanes and fixed runner blades. correct incorrect

It employs moving guide vanes and moving runner blades. correct incorrect

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4) The country with the largest hydropower capacity in 2019 was…

Brazil. correct incorrect

Canada. correct incorrect

China. correct incorrect

Norway. correct incorrect

USA. correct incorrect

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5) The power output of a dam is given by…

$\eta \rho ghQ$ correct incorrect

$\eta \rho Q\sqrt{gh}$ correct incorrect

$\eta \rho g{h}^{2}Q$ correct incorrect

$\eta \rho g{h}^2{Q}^2$ correct incorrect

$\eta \rho gh{Q}^3$ correct incorrect

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6) The maximum power output of a Pelton wheel is given by…

$\rho Qu$ correct incorrect

$\frac{1}{2}\rho Q{u}^3$ correct incorrect

$\frac{1}{2}\rho Q{u}^{\frac{1}{2}}$ correct incorrect

$\frac{1}{2}\rho Q{u}^2$ correct incorrect

$\sqrt{\rho Qu}$ correct incorrect

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7) The maximum efficiency of a reaction turbine is given by…

$u_1^2 q_1 \text{cos }{\beta }_1 /gh$ correct incorrect

$u_1{q}_1 \text{cos }{\beta }_1/\sqrt{gh}$ correct incorrect

$u_1{q}_1{\cos }^2{\beta }_1/gh$ correct incorrect

$u_1{q}_1 \text{cos }{\beta }_1/2gh$ correct incorrect

$u_1{q}_1 \text{cos }{\beta }_1/gh$ correct incorrect

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8) Euler's equation provides a formula for the power output from a turbine. Does the fact that the derivation takes no account of the details of the flow inside the turbine (where the blades do work on the fluid) invalidate the formula?

Yes correct incorrect

No correct incorrect

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9) Which of the following statements are true?
Please select all that apply.

Dams with high carbon emissions tend to occur in low-lying areas, while those with low carbon emissions are mainly in mountainous regions. correct incorrect

It has been estimated that 300,000 to 600,000 people worldwide have had to be relocated because of hydropower. correct incorrect

In 2019 pumped storage provided about 95% of global electricity storage. correct incorrect

Impulse turbines are suited for fast-moving mountain streams. Francis turbines are suitable for run-of-river sites and Kaplan turbines for large dams. correct incorrect

Hydropower was the largest source of renewable energy in 2019, providing about twice the electricity as solar plus wind power. correct incorrect

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10) The typical capacity factor of a dam is of order…

1%. correct incorrect

10%. correct incorrect

25%. correct incorrect

40%. correct incorrect

90%. correct incorrect

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11) The interval between high tides is about…

6 hours. correct incorrect

9.5 hours. correct incorrect

12 hours. correct incorrect

12.5 hours. correct incorrect

24 hours. correct incorrect

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12) The velocity of a tidal wave of wavelength λ in a sea of depth h is given by…

$\sqrt{gh}$ correct incorrect

$\sqrt{g\lambda }$ correct incorrect

$\sqrt{g\lambda /2\pi }$ correct incorrect

$\sqrt{g/h}$ correct incorrect

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13) The country with the largest tidal potential in Europe is…

France. correct incorrect

Germany. correct incorrect

Ireland. correct incorrect

Spain. correct incorrect

UK. correct incorrect

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14) The velocity of a surface wave on deep water is given by…

$g\lambda$ correct incorrect

$\sqrt{g\lambda }$ correct incorrect

$\sqrt{g\lambda /2\pi }$ correct incorrect

$\sqrt{2\pi g/\lambda }$ correct incorrect

$g/2\pi \lambda$ correct incorrect

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15) The total energy per unit width per unit length of a surface wave on deep water is given by…

$\frac{1}{2}\rho g{\lambda }^2$ correct incorrect

$\frac{1}{2}\rho g{a}^2$ correct incorrect

$\rho ga$ correct incorrect

$\frac{1}{4}\rho g{a}^2$ correct incorrect

$\frac{1}{2}\rho ga\lambda$ correct incorrect

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16) Which of the following statements are true?
Please select all that apply.

A Wells turbine spins in both directions. correct incorrect

The maximum efficiency of a Pelton wheel is obtained when the incident jet is not deflected. correct incorrect

Hydropower in the EU is quite well exploited, but the potential for growth elsewhere is considerable, particularly in Asia, Latin America, and Africa. correct incorrect

The energy of a wave in deep water increases with depth. correct incorrect

There would be no tides if the Moon did not exist. correct incorrect

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17) Which of the following statements are true?
Please select all that apply.

The turbine in an oscillating water column is submerged in water. correct incorrect

Euler's turbine equation can be applied to a Pelton Wheel. correct incorrect

Wave energy convertors tend to operate near to the shore. correct incorrect

TAPCHAN has no moving parts (excluding the turbine). correct incorrect

The speed of a Pelton Wheel is controlled by a spear valve. correct incorrect

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18) The maximum power output of a dam with a head of 100 m and a volume flow rate of 1 m³s^-1 is about…

1 kW. correct incorrect

10 kW. correct incorrect

100 kW. correct incorrect

1 MW. correct incorrect

10 MW. correct incorrect

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19) Which of the following statements are true?
Please select all that apply.

Hydropower tends to be state-funded due to its high capital cost. correct incorrect

Hydropower has no carbon footprint. correct incorrect

The largest tidal range globally is in the River Severn, UK. correct incorrect

Water waves on deep water are dispersive. correct incorrect

Submerged wave energy convertors, with OWCs where appropriate, are emerging as the preferred technologies. correct incorrect

There is a larger global potential for tidal range plants than for tidal stream plants. correct incorrect

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20) The accessible potential of hydropower by 2050 is about…

2000 TWh y^-1. correct incorrect

4000 TWh y^-1. correct incorrect

7000 TWh y^-1. correct incorrect

15000 TWh y^-1. correct incorrect