KSEEB Solutions for Class 8 Geography Chapter 4 Hydrosphere
KSEEB Solutions for Class 8 Geography Chapter 4 Hydrosphere
Karnataka State Syllabus Class 8 Social Science Geography Chapter 4 Hydrosphere
Class 8 Social Science Hydrosphere Textual Questions and Answers
I. Fill In The Blanks:
Question 1.
The average depth of the continental shelf is _______
Answer:
100 fathoms
Question 2.
One fathom is equal to _______
Answer:
6 ft
Question 3.
The deepest place in the pacific ocean is _______
Answer:
The challenger deep
Question 4.
The average salinity of the ocean water is _______
Answer:
35 PPT
Question 5.
_______ tides occur during full moon
Answer:
Spring
II. Answer The Following Questions:
Question 1.
What is a hydrosphere?
Answer:
The hydrosphere is the most important layer of earth. Nearly 71% of the total area of the earth is covered by water bodies like oceans, seas, lakes, rivers, etc. All these water bodies are called as Hydrosphere.
Question 2.
Mention the four major parts of the ocean floor.
Answer:
The four major parts of the ocean floor are
- The Continental Shelf
- The Continental slope
- The Deep sea plain and
- The Ocean deep.
Question 3.
State the difference between ocean currents and tides.
Answer:
Ocean currents:
- Ocean currents are the regular movement of ocean water from one region to another.
- Ocean currents are of two types ‘warm currents and cold currents.
Tides:
- Tides are the periodic rise and fall in the sea or ocean level.
- They occur due to gravitational attraction by the moon, gravitational force by the sun, rotation of the earth and centrifugal force of the earth.
- The two types of tides are spring tide and Neap tides.
Question 4.
Distinguish between spring tide and neap tide.
Answer:
Springtide: spring tides take place when the earth the moon and the Sun are in the same straight line. E.g. New moon and Full moon days.
Neap tides: Neap tides occur in the first quarter and last quarter days in the phase of the Moon. During this time the sun and the earth are in the same straight line and the moon is in a right angle to the earth.
Question 5.
How can we conserve the oceans?
Answer:
We can conserve oceans through following-methods:
- Oil transportation should be done through pipelines.
- Nuclear waste should not be dumped into the sea or ocean.
- Dumping of any waste near the ports and harbours must be controlled.
- Ore deposition and mineral exploitation along the coast must be controlled.
- Exploitation and destruction of beaches must be controlled.
III. MATCH THE FOLLOWING:
| A | B |
| 1. Fathom | (a) deep sea plain |
| 2. Oyashio | (b) eastern coast of U.S.A |
| 3. Gulf stream | (c) cold current |
| 4. Sea mounts | (d) Indian ocean |
| 5. Agulhas current | (e) depth of ocean |
Answer:
| A | B |
| 1. Fathom | (e) depth of the ocean |
| 2. Oyashio | (c) cold current |
| 3. Gulf stream | (b) eastern coast of U.S.A |
| 4. Seamounts | (a) deep-sea plain |
| 5. Agulhas current | (d) Indian ocean |
IV. Define The Following :
1. Continental shelf: This is the shallow area along the sea coast. This part is bordered by the sea coast on one side and continental slope on the other side. The average depth of the continental shelf is 100 fathoms.
2. Salinity: It is the percentage of salts dissolved in the sea or ocean water. The average salinity of the ocean water is 35 PPt. The salinity of ocean water is very high near the tropics and it is very low near the poles.
3. Warm and cold currents :
These currents originate and flow from the equatorial regions to subpolar regions. These currents originate in the Polar Regions and flow towards the equatorial region.
4. High tide and Low tide: The tide, also known as flood tide, and low tide also known as Ebb tide.
5. Benguela current: It is the South Atlantic Ocean cold current.
6. Tides: Tides are the periodic rise and fall in the sea or ocean level.
Class 8 Social Science Hydrosphere Additional Questions and Answers
I. Multiple Choice Questions:
1. The small semi-circular water bodies partially surrounded by land are called _____
(a) Bays
(b) Gulf
(c) Sea
(d) OceAnswer:
Answer:
(a) Bays
2. This is the shallow area along the sea coast _____
(a) Continental slope
(b) Continental shelf
(c) The deep-sea plain
(d) The ocean deep
Answer:
(b) Continental shelf
3. The deep-sea plain is also known as _____
(a) Ocean deep
(b) Deep-sea.
(c) Abyssal plain
(d) Obyssal plain.
Answer:
(c) Abyssal plain
4. The ocean deeps are also called _____
(a) Obyssal plain
(b) The ocean deep
(c) Abyssal plain
(d) Ocean trenches.
Answer:
(d) Ocean trenches.
5. The average salinity of the- ocean water is _____
(a) 35 PPT
(b) 37 PPT
(c) 36 PPT
(d) 39 PPT
Answer:
(a) 35 PPT
II. Fill In The Blanks:
Question 1.
______ are a deep and large expanse of water found between the continents.
Answer:
Oceans
Question 2.
______ is a part of an ocean or sea that penetrated into the land.
Answer:
Gulf
Question 3.
______ takes place when the earth, the moon, and the sun are in the same straight line.
Answer:
Spring tides
Question 4.
During ______ the sun and the earth are in the same straight line.
Answer:
Neap tides
Question 5.
The coldest place on earth is ______
Answer:
Vostots
III. Answer The Following Questions:
Question 1.
Why the temperature of the ocean water near the equator is more than Arctic Arctic and the Antarctic circles?
Answer:
It is because the sunlight can penetrate into the ocean only upto a depth of 200 meters.
Question 2.
What are ocean currents?
Answer:
Ocean currents are the regular movement of ocean water from one region to another.
Question 3.
Name the south Indian ocean currents.
Answer:
The south Indian ocean currents are Mozambique, Madagascar, Agulhas as warm currents and west Australian as cold currents.
Question 4.
What are tides? How do they occur?
Answer:
Tides are the periodic rise and fall in the sea or ocean level. They occur due to gravitational attraction by the moon, gravitational force by the sun, rotation of the earth, and centrifugal force of the earth.
Question 5.
Name the different kinds of tides.
Answer:
Springtide and Neap tide.
Question 6.
How are tides useful to mankind?
Answer:
Tides are directly and indirectly useful to mankind in the following ways. It helps navigation
- Helps in the location of ports and harbours.
- Tides help to keep the harbours clean.
- They help the fishing.
- Help to generate energy in the form of tidal energy.
V. Terms To Remember:
1. Gulf stream: Warm current.
2. Salinity: The percentage of salts dissolved in the sea or ocean water.
3. Warm current: It originates and flows from the equatorial regions to wub- polar regions.
4. Kuroshio current: Honshu Hokkaido fishing ground.
5. Flood tides: Flood tides.
6. Tidal energy: Generates electricity through tides.
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