Hydrosphere Book Back Questions & Answers
Unit 4 > Social > Class 9 > Samacheer Kalvi - English Medium
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1. The Sunda Trench lies in the ___________ ocean.
a) Atlantic
b) Pacific
c) Indian
d) Antarctic
Correct answer: c) Indian
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2. The temperature of the ocean waters generally_______ at greater depth.
a) increases
b) decreases
c) remains constant
d) none of the above
Correct answer: b) decreases
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3. Ocean currents are produced due to _________
a) due to rotation of earth
b) due to variation in temperature
c) due to earths movement
d) all the above
Correct answer: d) all the above
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4. Consider the following statements. 1. Most of the fishing grounds occur in areas where the continental shelf is wide. 2. Fishing is well developed in warm tropical waters. 3. Mixing of warm and cold currents facilitates plant nutrients for fish. 4.Inland fishing became significant in India.
a) 1 and 2 are correct.
b) 1 and 3 are correct.
c) 2,3 and 4 are correct.
d) 1,2 and 3 are correct
Correct answer: b) 1 and 3 are correct.
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5. The oceanic ridge comes into existence due to
a) convergence of tectonic plates .
b) divergence of tectonic plates
c) lateral movements of plates
d) stearing of plates.
Correct answer: b) divergence of tectonic plates
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6. Which of the following indicates the correct sequence of the topography beneath the surface of the sea?
a) Continental shelf-Continental slopeSea plain-Sea trench.
b) Continental slope-Continental shelfSea plain-Sea trench.
c) Sea plain-Continental slopeContinental shelf-Sea trench.
d) Continental slope-Sea plainContinental shelf-Sea trench
Correct answer: a) Continental shelf-Continental slopeSea plain-Sea trench.
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7. Which of the following is not correctly matched?
a) Gulf Stream - Pacific Ocean
b) Labrador current - North Atlantic Ocean
c) Canary current - Mediterranean sea
d) Mozambique current - Indian Ocean.
Correct answer: a) Gulf Stream - Pacific Ocean & c) Canary current - Mediterranean sea
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8. The amount of planktons to be found in the ocean is determined by 1. Depth of the water. 2. Ocean currents. 3. Temperature and Salinity. 4. Length of day and night.
a) 1 and 2 are correct
b) 1,2 and 3 are correct
c) 1,3 and 4 are correct
d) All are correct
Correct answer: d) All are correct
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1. (A): Assertion (A): Oceans are always shown in blue in maps... (R): Reason(R): It indicates the natural colour of the oceans
a) Both A and R are correct and R explains A.
b) Both A and R are correct but R does not explain A.
c) A is correct but R is false.
d) A is false but R is correct
Correct answer: a) Both A and R are correct and R explains A.
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2. (A): Assertion(A): Flat topped seamounts are known as Guyots... (R): Reason(R): All guyot features are of volcanic origin
a) Both A and R are correct and R explains A.
b) Both A and R are correct but R does not explain A.
c) A is correct but R is false.
d) A is false but R is correct
Correct answer: a) Both A and R are correct and R explains A.
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3. (A): Assertion(A): Submarine canyons are deep gorges on the ocean floor... (R): Reason(R): They are mainly restricted to continental shelf, slope and rise
a) Both A and R are correct and R explains A.
b) Both A and R are correct but R does not explain A.
c) A is correct but R is false.
d) A is false but R is correct
Correct answer: b) Both A and R are correct but R does not explain A.
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4. (A): Assertion (A): Atolls are more common in the Atlantic ocean... (R): Reason(R): The marine population at the depth is less
a) Both A and R are correct and R explains A.
b) Both A and R are correct but R does not explain A.
c) A is correct but R is false.
d) A is false but R is correct
Correct answer: d) A is false but R is correct
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1. Mariana trench
Correct answer: Deepest point in the Pacific
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2. Great Barrier Reef
Correct answer: Australia
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3. Sargasso sea
Correct answer: North Atlantic Ocean
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4. Spring tides
Correct answer: On full and new moon days
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5. Heavy rains
Correct answer: Decreases salinity in the oceans
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6. Kuroshio current
Correct answer: Along the coast of Japan
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7. Continental slope
Correct answer: Second order landform