Tidal, Wave & Geothermal Energy - UNSOLVED PAPER SET
Chapter: Sources of Energy | Topic: Tidal Wave and Geothermal Energy
TIDAL, WAVE & GEOTHERMAL ENERGY - UNSOLVED PAPER SET
Topic: Tidal Wave and Geothermal Energy
Multiple Choice Questions
Q1. Which of the following is the primary cause of tides in the ocean?
- Rotation of the Earth on its axis
- Gravitational pull of the Moon on Earth's water bodies
- Strong winds blowing over the sea surface
- Temperature difference between ocean surface and deep water
Q2. In a tidal energy power plant, electricity is generated when:
- Water is pumped into the dam during low tide
- Water flows back to the ocean during low tide through turbines
- Waves crash against the shore continuously
- Hot water from the ocean surface is boiled
Q3. Geothermal energy is considered unique because:
- It is available only during daytime
- It does not ultimately depend on solar energy
- It can only be harnessed near the equator
- It requires very large dams for electricity generation
Q4. For ocean thermal energy conversion (OTEC) to be feasible, the minimum temperature difference required between surface water and deep water is:
- 10°C
- 15°C
- 20°C
- 30°C
Q5. In wave energy devices, when waves rush into a hollow tower, the kinetic energy of which substance is used to run the turbine?
- Seawater rushing into the tower
- Air forced upwards by the entering water
- Steam produced by heating seawater
- Molten rocks beneath the ocean floor
Q6. Hot springs and geysers (like those found in Manikaran, Himachal Pradesh) are examples of:
- Tidal energy sources
- Wave energy sources
- Natural manifestations of geothermal energy
- Solar thermal collectors
Short Answer Questions
Q7. Explain how tidal energy is harnessed using a dam built across a narrow opening of the sea. Why is this source of energy limited to only a few places?
Q8. Describe the working of a device used to harness wave energy. Why is wave energy not yet widely used for commercial electricity generation?
Q9. What is geothermal energy? Name two locations in India where geothermal energy potential exists.
Q10. Why is geothermal energy said to be the only form of energy that does not ultimately come from the Sun? Explain with reference to its origin.
Q11. A student visits the coastal town of Dwarka in Gujarat and observes very high tides. Suggest two ways by which the energy of these tides could be converted into useful electrical energy. Mention one limitation of each method.
Q12. Ocean thermal energy conversion (OTEC) uses ammonia as a working fluid. Explain why ammonia is preferred over water in this process.
Long Answer Questions
Q13. Compare and contrast tidal energy, wave energy, and ocean thermal energy under the following heads:
(i) Basic principle of energy conversion
(ii) Minimum requirements for harnessing
(iii) Major limitations
(iv) Environmental impact
Q14. Explain the process of harnessing geothermal energy with a neat diagram description. Discuss any two advantages and two limitations of using geothermal energy as a source of power.
Q15. Imagine you are the head of a coastal village in Tamil Nadu that experiences strong waves and high tides. Your village needs a reliable source of electricity. Evaluate whether tidal energy or wave energy would be more suitable for your village. Give reasons for your choice, considering factors like cost, reliability, and environmental impact.
Numerical / Application-Based Problems
Q16. A tidal power plant operates with a tidal range (difference between high tide and low tide water levels) of 8 metres. The surface area of the tidal basin is 20 km². Given that the density of seawater is 1025 kg/m³ and acceleration due to gravity g = 9.8 m/s², calculate the potential energy available during one tidal cycle.
(Hint: Use the formula for gravitational potential energy: PE = mgh, where m = density × volume)
Q17. A geothermal power plant produces 50 MW of electrical power. If the plant operates for 24 hours a day, calculate:
(a) The total energy produced in one day (in MWh)
(b) The number of households it can power for one day, if each household consumes 10 kWh per day
Q18. In an OTEC system, warm surface water at 28°C is used to vaporize ammonia, while cold deep water at 4°C is used to condense it back.
(a) Calculate the temperature difference driving the system.
(b) If the efficiency of the heat engine is only 3% due to the small temperature difference, and the heat absorbed from the warm water is 500 MJ, calculate the useful work output.