KSEEB Solutions for Class 8 Geography Chapter 4 Hydrosphere

/ By

Students can Download Geography Chapter 4 Hydrosphere Questions and Answers, Notes Pdf, KSEEB Solutions for Class 8 Social Science helps you to revise the complete Karnataka State Board Syllabus and to clear all their doubts, score well in final exams.

Karnataka State Syllabus Class 8 Social Science Geography Chapter 4 Hydrosphere

Class 8 Social Science Hydrosphere Textbook Exercise Questions and Answers

I. Fill in the blanks with suitable words :

1. The average depth of the continental shelf is _______________ .
2. One fathom is equal to _______________ ft.
3. The deepest place in the Pacific ocean is _______________ .
4. The average salinity of the ocean water is _______________ .
5. _______________ tides occur during the full moon.
Answers :
1. 100 fathers,
2. Six,
3. the challenger deep,
4. 35 PPT,
5. Spring

KSEEB Solutions

II. Answer the following questions :

Question 1.
What is a hydrosphere?
Answer :
About 71 % of the total area of the earth of 361 million sq. Km is covered by water is called hydrosphere.

Question 2.
Mention the four major parts of the ocean floor.
Answer :
The four major parts of the ocean floor are. The Pacific Ocean, the Atlantic ocean, the Indian ocean, and the Arctic ocean.

Question 3.
State the difference between ocean current and tides.
Answer :

  • Ocean current: The ocean currents are the regular movement of ocean water from one region to another. They 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 the gravitational attraction of the moon, the sun, rotation of the earth, and centrifugal force of the earth.

KSEEB Solutions

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,
Eg: New Moon and Full Moon high tides are the highest and the low tides are the lowest.
Neap Tide: Neap tides occur on the first quarter and last quarter days in the phase of the Moon.

Question 5.
How can we conserve the oceans?
Answer :
The following methods should be followed to conserve the oceans.

  1. Proper care should be taken in transporting oil products-pipe lines.
  2. Nuclear waste should not be dumped into the sea or ocean.
  3. Waste materials, garbage should not be dumped.
  4. Ore deposition and mineral exploitation along the coastline must be controlled.
  5. Exploitation and destruction of beaches must be controlled.

KSEEB Solutions

III. Match the following :
A – B
1. fathom – (a) deep-sea plain
2. oyashio – (b) eastern coast of USA
3. gulf stream – (c) cold current
4. seamounts – (d) Indian ocean current.
5. Agulhas current – (e) depth of the ocean
Answers:
1. e,
2. c,
3. b,
4. a,
5. d

IV. Define the following :

  1. Continental shelf: It is the shallow area along the sea coast. It is bordered by the sea coast and continental slope. The average depth of the continental depth is 100 fathoms. This is very important for fishing aquaculture, navigation and extraction of minerals.
  2. Salinity: Salinity 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 the ocean water is very high near the tropics and it is very low near the poles.
  3. Warm and cold currents: Warm currents: These currents originate and flow from the equatorial regions to the sub-polar regions. Cold currents: These currents originate in the polar regions and flow towards the equatorial regions.
  4. High tide and low tide: High tide: On New Moon and Full moon days the sun, the moon and the earth are almost in the same straight line. Because the gravitational force of the sun and the moon high tides take place. These are called high tides or spring tides.
  5. Low tides: On the First Quarter and the Last Quarter days of in the phase of the moon, neap tides occur. During this time the Sun, the earth are in the same straight but the moon in the right angle to the earth. The effect of the gravitational force is more than the sun. So the tides of this time occur are called low tides or neap tides.
  6. Bcngucla current: Benguela currents are the cold currents of the South Atlantic ocean. They flow from the south polar region to the equatorial region.
  7. 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 and centrifugal force of the earth. Tides are helpful to the entry of the large ships to the harbor. They clean up the coastal area. They are helpful to produce electricity.

KSEEB Solutions

V. Terms to remember :

  1. Gulf stream: Gulf stream is a warm current of the North Atlantic ocean. The meeting place of Gulf stream warm current and Labrador cold currents are called as Grand bank of the fishery.
  2. Salinity: Salinity is the percentage of salts dissolved in the sea or ocean water.
  3. Warm currents: Warm currents originate and flow from the equatorial regions to the polar region. They are helpful to raise the temperature of polar regions.
  4. Kuroshio current: Kuroshio is the warm current of the Pacific ocean. The meeting place Kuroshio warm current and Oyashio cold current are the major fishing grounds of Japan.
  5. Flood tides: During the full moon and New moon days and on the days of lunar and solar eclipse flood tides are common on those days the sun, the earth, and the moon are in a straight line.
  6. Tidal energy: Energy of the tides can be converted into tidal energy to produce electricity. In India, two areas are pointed out to generate tidal energy. They are the Gulf of Kuchchh in Gujarath state and Sundarbans in West Bengal.