4 Distribution of Continents and Oceans

Multiple Choice Questions

1.Choose the right answers of the following! from the given options:

1.Who amongst the following was the first to consider the possibility of Europe, Africa and America having been located side by side?

(a) Alfred Wegener    (b) Antonio Pellegrino

(c) Abraham Ortelius  (d)Edmond Hess

2.Polar fleeing force relates to:

(a) Revolution of the Earth      (b) Gravitaion

(c) Rotation of the earth '            (d) Tides

3.Which one of the following is not a minor plate? {o) Nazca .          (b) Arabia

(c) Philippines.           I            (d) Antarctica

4.Which one of the following facts was not considered by those while discussing the concept of sea floor spreading?

(?)Volcanic activity along the mid-oceanic ridges.

(?)Stripes of normal and reverse magnetic field observed in rocks of ocean floor, (c) Distribution of fossils in different continents.

Age of rocks from the ocean floor.

5.Which one of.the folioing is the type of plate boundary of the Indian plate along the Himalayan mountains?

(a)Ocean-continent convergence

(b)Divergent boundary

(c)Transform boundary

(d)Continent-continent convergence

Ans. 1. (c), 2. (c). 3. (d), 4. (c), 5. (d).

(e)Short Answer Questions J

2.Answer the following questions in about 30 words:

1.What were the forces suggested by Wegener for the movement of the continents?

 Ans. Wegener suggested that two forces were responsible for continental drift.

These are (1)

Polar fleeing force

(2) Tidal force.

The Polar fleeing force is related to the rotation of the

earth. The Tidal force is due to the attraction of the moon and the sun which causes tides

in the oceans.

2.How are the convectional currents in the mantle initiated and maintained? Ans. The convectional currents in the mantle of the earth are initiated and maintained by

temperature differences within the earth. Hot magma from greater depths comes up and comparatively cold lava from above goes down giving birth to convectional currents.



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