Hydrosphere - Practice Test 1

Attempt the quiz above first, then review every question with its correct answer and a short explanation below.

1. Q1.What percentage of the Earth's surface is covered by water?

   • A.50%
   • B.60%
   • C.71%✓ Correct Answer
   • D.80%

   Explanation: Approximately 71% of the Earth's surface is covered by the Hydrosphere.

2. Q2.Which hemisphere is known as the 'Water Hemisphere'?

   • A.Northern Hemisphere
   • B.Southern Hemisphere✓ Correct Answer
   • C.Eastern Hemisphere
   • D.Western Hemisphere

   Explanation: The Southern Hemisphere has significantly more water coverage (81%) compared to the Northern.

3. Q3.The largest ocean in the world is:

   • A.Atlantic Ocean
   • B.Indian Ocean
   • C.Pacific Ocean✓ Correct Answer
   • D.Arctic Ocean

   Explanation: The Pacific Ocean is the largest and deepest ocean.

4. Q4.The deepest point in the oceans, Mariana Trench, is located in:

   • A.Atlantic Ocean
   • B.Pacific Ocean✓ Correct Answer
   • C.Indian Ocean
   • D.Arctic Ocean

   Explanation: It is located in the western Pacific Ocean.

5. Q5.Which ocean is 'S-shaped'?

   • A.Pacific Ocean
   • B.Atlantic Ocean✓ Correct Answer
   • C.Indian Ocean
   • D.Southern Ocean

   Explanation: The Atlantic Ocean separates the Americas from Europe/Africa, forming an 'S' shape.

6. Q6.The shallowest part of the ocean floor adjoining the continents is called:

   • A.Continental Slope
   • B.Continental Shelf✓ Correct Answer
   • C.Abyssal Plain
   • D.Oceanic Trench

   Explanation: The Continental Shelf is the gently sloping submerged border of a continent.

7. Q7.The flat, deep ocean floor is known as:

   • A.Continental Rise
   • B.Abyssal Plain✓ Correct Answer
   • C.Shelf
   • D.Ridge

   Explanation: Abyssal Plains are extensive flat areas of the deep ocean.

8. Q8.Isohalines are lines connecting places of equal:

   • A.Temperature
   • B.Salinity✓ Correct Answer
   • C.Depth
   • D.Pressure

   Explanation: Isohalines map ocean salinity.

9. Q9.The average salinity of ocean water is:

   • A.35 ppt (parts per thousand)✓ Correct Answer
   • B.10 ppt
   • C.50 ppt
   • D.75 ppt

   Explanation: Average ocean salinity is 35 parts per thousand (3.5%).

10. Q10.Which sea has the highest salinity in the world?

    • A.Dead Sea
    • B.Red Sea
    • C.Lake Van✓ Correct Answer
    • D.Great Salt Lake

    Explanation: Lake Van (Turkey) has a salinity of ~330 ppt. (Dead Sea is ~240 ppt).

11. Q11.The most abundant salt in ocean water is:

    • A.Calcium Carbonate
    • B.Sodium Chloride✓ Correct Answer
    • C.Magnesium Chloride
    • D.Potassium Sulfate

    Explanation: Sodium Chloride (Common Salt) constitutes nearly 77.8% of ocean salts.

12. Q12.Lines joining places of equal depth in the ocean are called:

    • A.Isobars
    • B.Isohyets
    • C.Isobaths✓ Correct Answer
    • D.Isotherms

    Explanation: Isobaths map ocean depth.

13. Q13.Ocean currents are caused by:

    • A.Planetary Winds
    • B.Earth's Rotation (Coriolis)
    • C.Difference in Temperature/Salinity
    • D.All of the above✓ Correct Answer

    Explanation: Winds, rotation, and density differences all drive currents.

14. Q14.Which of these is a Warm Ocean Current?

    • A.Labrador Current
    • B.Canary Current
    • C.Gulf Stream✓ Correct Answer
    • D.Benguela Current

    Explanation: The Gulf Stream is a strong warm current in the Atlantic.

15. Q15.Which of these is a Cold Ocean Current?

    • A.Kuroshio Current
    • B.Brazilian Current
    • C.Agulhas Current
    • D.Labrador Current✓ Correct Answer

    Explanation: Labrador Current brings cold water from the Arctic to the Atlantic.

16. Q16.The Sargasso Sea is located in which ocean?

    • A.Pacific Ocean
    • B.North Atlantic Ocean✓ Correct Answer
    • C.Indian Ocean
    • D.South Atlantic Ocean

    Explanation: It is a region of calm water and seaweed in the North Atlantic gyre.

17. Q17.The Gulf Stream and Labrador Current meet near:

    • A.Newfoundland✓ Correct Answer
    • B.Japan
    • C.Florida
    • D.Brazil

    Explanation: Their meeting creates fog and rich fishing grounds near Newfoundland (Grand Banks).

18. Q18.Which current is responsible for the mild climate of Western Europe?

    • A.Canary Current
    • B.North Atlantic Drift✓ Correct Answer
    • C.Labrador Current
    • D.Benguela Current

    Explanation: The warm North Atlantic Drift keeps European ports ice-free.

19. Q19.The periodic rise and fall of sea water level is called:

    • A.Waves
    • B.Currents
    • C.Tides✓ Correct Answer
    • D.Tsunami

    Explanation: Tides are caused by the gravitational pull of the Moon and Sun.

20. Q20.Spring Tides occur when:

    • A.Sun, Moon, Earth are at right angles
    • B.Sun, Moon, Earth are in a straight line✓ Correct Answer
    • C.Moon is farthest
    • D.Sun is farthest

    Explanation: During Full Moon and New Moon (Syzygy), combined gravity causes high tides.