Imp Questions For All Chapters – Geography Class 7
Tides
Short Questions
1. What are tides?
Answer: Tides are the regular rise and fall of seawater caused by the gravitational pull of the moon and sun.
2. What is the time difference between two high tides?
Answer: The time difference between two high tides is 12 hours and 25 minutes.
3. What is the main cause of tides?
Answer: Tides are mainly caused by the gravitational force of the moon and the sun along with Earth’s centrifugal force.
4. What is a spring tide?
Answer: A spring tide is a very high tide that occurs on full moon and new moon days due to the combined pull of the sun and moon.
5. What is a neap tide?
Answer: A neap tide is a weaker tide that occurs during the first and third quarter phases of the moon, when the sun and moon’s forces act at right angles.
6. What is the tidal range?
Answer: The tidal range is the difference in the water level between high tide and low tide.
7. Which place has the highest tidal range in the world?
Answer: The Bay of Fundy in Canada has the highest tidal range in the world, about 1600 cm.
8. How do tides help in fishing?
Answer: During high tide, seawater enters creeks, bringing fish closer to the shore, making it easier to catch them.
9. What is a tsunami?
Answer: A tsunami is a massive sea wave caused by an underwater earthquake or volcanic eruption, leading to destruction along coastlines.
10. How do tides help in electricity generation?
Answer: Tidal energy plants use the movement of tides to generate electricity from the rising and falling water levels.
Long Questions
1. Explain the role of the moon in causing tides.
Answer: The moon’s gravitational pull attracts seawater, causing it to rise, creating high tides. Since the moon is closer to Earth than the sun, its influence on tides is stronger.
2. How does centrifugal force affect tides?
Answer: The Earth’s rotation creates a centrifugal force that pushes seawater outward, forming a second high tide on the opposite side of the Earth.
3. Why do places on opposite meridians experience tides at the same time?
Answer: Due to the combined effects of gravitational and centrifugal forces, when high tide occurs at one place, another high tide occurs at the exact opposite meridian on Earth.
4. Differentiate between spring tide and neap tide.
Answer: A spring tide occurs during the full moon and new moon when the sun and moon’s pull are combined, creating the highest high tide. A neap tide occurs during the first and third quarter of the moon when their forces act at right angles, reducing tidal height.
5. What are the benefits of tides for human activities?
Answer: Tides help in fishing, port navigation, salt production, and electricity generation, while also cleaning coastal areas by washing away waste materials.
6. How do tides help in keeping the coastal environment clean?
Answer: High tides wash away waste and debris from coastal areas, preventing pollution, while also helping in the natural maintenance of mangroves and marine life.
7. Explain the difference between high tide and low tide.
Answer: High tide occurs when seawater rises due to the strong gravitational pull, covering more land, while low tide occurs when water recedes, exposing the shoreline.
8. What causes waves in the ocean?
Answer: Waves are mainly caused by wind, but they can also be created by underwater earthquakes or volcanic eruptions, leading to large and dangerous waves like tsunamis.
9. What is the effect of tides on coastal biodiversity?
Answer: Tides help in maintaining mangrove forests, marine ecosystems, and coastal habitats by ensuring a regular flow of seawater and nutrients.
10. Why is it important to know tidal timings before entering the sea?
Answer: Knowing tidal timings is important to avoid accidents, as high tides can be dangerous for swimming and coastal activities, while low tides can expose rocks and sea creatures.
Leave a Reply