Karnataka State Board Social Science Geography Class 8 Chapter 4 Hydrosphere Exercise Question and Answer.
I Fill in the blanks with suitable words :
1.) The average depth of the continental shelf is 100 fathoms.
2.) One fathom is equal to 6 ft.
3.) The deepest place in the Pacific ocean is Mariana trench.
4.) The average salinity of the ocean water is35 PPT.
5.) Spring tides occur during full moon.
1.) What is hydrosphere?
Answer –Hydrosphere is water bodies of the world are the Pacific ocean, the Atlantic ocean, the Indian ocean and the Arctic ocean.
2.) Mention the four major parts of the ocean floor.
Answer – The four major parts of the Ocean Floor as as follows,
a) The continental shelf
b) The continental slope
c) The deep sea plain
d) The ocean deeps
3.) State the difference between ocean currents and tides.
4.) Answer – Oceans – Ocean currents are the regular movement of ocean water from one region to another. Ocean currents are of two types a) Warm currents and b) Cold currents.
Tides – Tides are the periodic rise and fall in the sea or ocean level.
Tides are of two types a) High Tide and b) Low Tide.
5.) Distinguish between spring tide and neap tide.
Answer –
Spring Tide | Neap Tide |
1. Spring tides take place when the earth, the moon and the sun are in the same straight line | 1. Neap tides occur on the first quarter and last quarter days in the phase of the Moon. |
2. When the spring tides take place, high tides are the highest and low tides are the lowest. | 2.neap tides the sun and the earth are in the same straight line and moon is in right angle to the earth. |
3. Eg:- New moon and Full moon. | 4. Eg:- High Tide and Low Tide. |
5.) How can we conserve the oceans?
Answer – By controlling the following we can conserve the ocean,
a) Oil transportation should be done through pipelines Drinking water sources must be kept clean.
b) Nuclear waste should not be dumped into the sea or ocean.
c) Petro-chemical industries in the coastal regions must avoid dumping effluents into the sea or ocean.
d) Dumping of any waste near the ports and harbours must be controlled.
e) Ore deposition and mineral exploitation along the coast must be controlled.
f) Exploitation and destruction of beaches must be controlled.
III) Match the following :
A B Answer
1. fathom a) deep sea plain a) Depth of ocean 2. oyashio b) eastern coast of USAb)Cold current 3. gulf stream c) cold current c)Eastern coast of USA 4. sea mounts d) Indian ocean currentd)Deeep Sea Plain 5. agulhas current e) depth of ocean e)Indian ocean current |
IV Define the following :
1.) Continental shelf
2.) Answer – Continental shelf is the second part of the ocean floor and it is very steep. It is a link between the continental shelf and the deep sea plain. Sub-marine canyons are a special feature in this region.
3.) Salinity
Answer – Salinity is the percentage of salts dissolved in the sea or ocean water.
4.) Warm and Cold currents.
Answer – Warm currents:These currents originate and flow from the equatorial regions to sub-polar regions.
Cold currents:These currents originate in the polar regions and flow towards the equatorial region.
5.) High tide and Low tide
Answer – High tide, also known as Flood tide. Low tide, also known as Ebb tide.
5.) Benguela current
Answer –It is South alantic ocean cold current.
6.) Tides
Answer – Tides are the periodic rise and fall in the sea or ocean level.
(1). The average depth of the continental shelf is ______. – 1 fathom.
(2). One fathom is equal to _______ ft. – 6ft
(3). The deepest place in the Pacific Ocean is _______. – Abyssal plain
(4). The average salinity of the ocean water is ______. – 35 PPT
(5). During full moon._______ tides occur – spring.
Answer the following questions:
(1). What is hydrosphere?
Ans: – We will call the water part of the earth hydrosphere.
(2).Mention the four major parts of the ocean floor.
Ans: – The main four parts of Ocean floor are –
(i) Continental shelf.
(ii) Continental slope.
(iii) The deep sea plain.
(iv) The ocean deep.
(3). State the difference between ocean currents and tides.
Ans:-
Ocean currents | Tide |
(i) Currents change their direction seasonally. | (i) Periodic rise |
(ii) Ocean current are two type – warm and cold | (ii) Tides are two types flood tide and low tide |
(4). Distinguish between spring tide and neap tide.
Spring Tide | Neap Tide |
i) Its occur when the earth moon and sun are in the some straight line | i) Its occur on the first quarter and last quarter days in the phase of the moon |
ii) High tides are the highest and low tides are the lowest. | ii) This type of tidles high tides are not high low tides are not low. |
(5). How can we conserve the oceans?
Ans: – We can conserve ocean by different way these are the ways-
(i) Ore deposition and mineral exploitation must be controlled.
(ii) Destruction of beaches must be controlled.
(iii) Dumping effluents into sea or ocean must be controlled.
(iv) Nuclear waste should not be dumped into the sea or ocean.
III. Match the following:
Define the following:
(1). Continental shelf:-
Ans: – The shallow area along the sea coast this is very important for fishing, Aquaculture and extraction of minerals.
(3). Warm and Cold currents:-
Ans: – Two type of currants –
(i) Warm currants ii) low currants.
Warm currant originated and flow from the equatorial regions. Lows are originated in the Polar Regions and flow towards the equatorial region.
(4). High tide and Low tide:-
Ans: – Tides are of two type’s High tide, also known as flood tide and low tide, also known as Ebb tide. On the water bodies of the earth there are alternate high tide and low tides.
(5). Benguela current:-
Ans: – Benguela currant is a cold currant of south Atlantic ocean .
(6). Tides:-
Ans: – It is a periodic rise and fall in the sea or ocean level. This is occur due to gravitational attraction by the moon force by the sun and centrifugal force of the earth.