15. Pick up the correct statement from the following :
A. The tides at any place occur a little less than 1 hour later, each succeeding day
B. The difference in time in solar hours and minutes from any lunar transit to the succeeding transit, is called high water level
C. The influence of the earth's gravity alone produces level-tidal less sea
D. All of the above.
16. Flow of air from one place to the other is caused due to
A. the sum of elevation
B. pressure head
C. velocity head
D. all of the above.
17. The variation of atmospheric potential is caused due to:
A. difference in temperature over the surface of the earth
B. change in the density of air
C. both (a) and (b)
D. neither (a) nor (b).
18. In tropical regions
A. the surface gets heated more effectively than the arctic areas
B. after heating, the air becomes lighter and is displaced by cool air from the polar regions
C. the rising tropical air flows towards the polar region in the upper strata
D. all of the above.
19. Pick up the correct statement from the following
A. The maritime structures should be designed to withstand wave motion of air
B. The wind vortex results in conical depression in the air surface
C. A tube of air rotating at hundreds of kilometres per hour forms a tornado
D. all of the above.
20. If F is the fetch, the straight line distance of open water available in kilometres, the height of the wave in metres is
A. 0.15 -/Y
B. 0.20 T"
C. 0.28 4-.F
D. 0.34 -4-P7.
21. On the sea shore structures, the water wave impact causes
A. direct compressive force due to its horizontal component
B. shear force due to deflected vertical force
C. compressive force due to collapse of the wave
D. all of the above.
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