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CBSE · Class 9 · Social Science

Oceans and Life

Standard difficulty · 20 questions · 40 marks

Name: Date: Score: ____ / 40

Write full answers in Sections B and C. Answers are on the last page — try every question first!

Section A — Choose the correct answer8 × 1 = 8 marks
1.
The deepest place on Earth is the:
  1. Mid-Ocean Ridge
  2. Singapore Strait
  3. Gulf of Khambhat
  4. Mariana Trench
2.
What is a continental slope?
  1. the steep slope marking a continent’s true edge
  2. the deepest part of the ocean floor
  3. a flat-topped underwater mountain
  4. a volcanic underwater mountain below the surface
3.
What is meant by “ebb tide”?
  1. how high a tsunami reaches on shore
  2. peaceful transit of a ship through territorial waters
  3. the high point of a wave
  4. low tide
4.
Which describes the Exclusive Economic Zone?
  1. a cold current off Canada’s east coast
  2. a warm current that keeps Norway’s waters ice-free
  3. up to 200 nautical miles from the baseline
  4. up to 24 nautical miles from the baseline
5.
What is NCRMP concerned with?
  1. storm-surge warnings
  2. defining maritime zones
  3. rules against pollution from ships
  4. cyclone shelters and warnings
6.
One nautical mile is 1,852 m. How many metres is 47 nautical miles?
  1. 87,044 m
  2. 88,896 m
  3. 47,000 m
  4. 75,623 m
7.
A current moves at 6 knots. One knot is 1 nautical mile (1.852 km) an hour. About how many km an hour is that, to one decimal place?
  1. 13.0 km/h
  2. 9.7 km/h
  3. 11.1 km/h
  4. 6 km/h
8.
A fishermen’s alert device reaches 50 nautical miles; an upgrade will reach 250. How many times farther is that?
  1. 6 times
  2. 200 times
  3. 5 times
  4. 250 times
Section B — Short answer8 × 2 = 16 marks
9.
What is submarine relief?
10.
Describe each feature of the ocean floor: (a) guyot (b) trench
11.
Explain each term: (a) bathymetry (b) trough
12.
What is each concerned with? (a) UNCLOS (b) COLREGs
13.
A ship is 218 nautical miles from India’s baseline. How many km is that, to one decimal place (1 nautical mile = 1.852 km), and which zone is it in?
14.
At a port, high tide reaches 12 m and low tide 7 m above a mark. What is the tidal range? Would this be a spring or a neap tide if the range is the largest of the month?
15.
A cyclone-name list has 143 names sent equally by 13 countries. How many names did each country send?
16.
What does the chapter say about (a) the high seas (b) the contiguous zone?
Section C — Longer answers4 × 4 = 16 marks
17.
Describe the main features of the ocean floor.
18.
Match each with its description: (a) seamount (b) guyot (c) trench. Choose from: a flat-topped underwater mountain; the deepest part of the ocean floor; a volcanic underwater mountain below the surface.
19.
Two fishing boats are 163 and 372 nautical miles from India’s baseline. (a) Convert both to km (1 nautical mile = 1.852 km), to one decimal place. (b) Which boat is inside India’s Exclusive Economic Zone? (c) Why are such zones agreed under UNCLOS?
20.
Explain “trough” and “Coriolis force”, and say how waves or tides affect people living on the coast.
AmbifulWorksheets
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CBSE · Class 9 · Social Science

Answer key

Oceans and Life · AW-9SS-OAL-2026-V1 · For parents — fold back or tear off before handing the sheet to your child.

QAnswerWorking
1(d) Mariana Trench—
2(a) the steep slope marking a continent’s true edge—
3(d) low tide—
4(c) up to 200 nautical miles from the baseline—
5(d) cyclone shelters and warnings—
6(a) 87,044 m47 × 1,852
7(c) 11.1 km/h6 × 1.852
8(c) 5 times250 ÷ 50
9The landforms of the ocean floor, such as underwater mountains, valleys, plateaus and trenches.—
10(a) a flat-topped underwater mountain (b) the deepest part of the ocean floor—
11(a) mapping the ocean floor (b) the low point between waves—
12(a) defining maritime zones (b) rules to avoid collisions at sea—
13403.7 km; the high seas218 × 1.852
145 m; a spring tide12 − 7
1511143 ÷ 13
16(a) about 64% of the oceans, beyond all EEZs (b) up to 24 nautical miles from the baseline—
17The continental shelf near land, the steep continental slope, the flat abyssal plain, deep trenches, and underwater mountains such as seamounts, guyots and the Mid-Ocean Ridge.—
18(a) a volcanic underwater mountain below the surface (b) a flat-topped underwater mountain (c) the deepest part of the ocean floor—
19(a) 301.9 km and 688.9 km (b) the boat at 163 nautical miles (the EEZ reaches 200) (c) So that countries share the seas fairly and avoid disputes.163 × 1.852; 372 × 1.852
20trough: the low point between waves; Coriolis force: deflection caused by the Earth’s rotation. Effects such as fishing at high tide, ships waiting for tides, or coastal erosion.—