Insights Revision Plan for Prelims 2016: Test – 42

Solution: d)

NCERT Class XI, Fundamentals of Physical Geography, Page – 72

https://www.britannica.com/science/deflation-geomorphology#ref65490

http://www.revision.co.zw/deflation-hollows/

Solution: d)

Crescent shaped dunes called barchans with the points or wings directed away from wind direction i.e., downwind, form where the wind direction is constant and moderate and where the original surface over which sand is moving is almost uniform. Parabolic dunes form when sandy surfaces are partially covered with vegetation. That means parabolic dunes are reversed barchans with wind direction being the same. Seif is similar to barchan with a small difference. Seif has only one wing or point. This happens when there is shift in wind conditions. The lone wings of seifs can grow very long and high. Longitudinal dunes form when supply of sand is poor and wind direction is constant. They appear as long ridges of considerable length but low in height. Transverse dunes are aligned perpendicular to wind direction. These dunes form when the wind direction is constant and the source of sand is an elongated feature at right angles to the wind direction. They may be very long and low in height.

NCERT Class XI, Fundamentals of Physical Geography, Page – 72

Solution: c)

NCERT Class XI, Fundamentals of Physical Geography, Page – 77

The mesosphere lies above the stratosphere, which extends up to a height of 80 km. In this layer, once again, temperature starts decreasing with the increase in altitude and reaches up to minus 100° C at the height of 80 km. The upper limit of mesosphere is known as the mesopause. The ionosphere is located between 80 and 400 km above the mesopause. It contains electrically charged particles known as ions, and hence, it is known as ionosphere. Radio waves transmitted from the earth are reflected back to the earth by this layer. Temperature here starts increasing with height.

Solution: a)

NCERT Class XI, Fundamentals of Physical Geography, Page – 80

The atmosphere is largely transparent to short wave solar radiation. The incoming solar radiation passes through the atmosphere before striking the earth’s surface. Within the troposphere water vapour, ozone and other gases absorb much of the near infrared radiation.

Solution: c)

NCERT Class XI, Fundamentals of Physical Geography, Page – 80

The insolation received at the surface varies from about 320 Watt/m2 in the tropics to about 70 Watt/m2 in the poles. Maximum insolation is received over the subtropical deserts, where the cloudiness is the least. Equator receives comparatively less insolation than the tropics. Generally, at the same latitude the insolation is more over the continent than over the oceans. In winter, the middle and higher latitudes receive less radiation than in summer

Solution: b)

NCERT Class XI, Fundamentals of Physical Geography, Page – 91

The pattern of planetary winds largely depends on : (i) latitudinal variation of atmospheric heating; (ii) emergence of pressure belts; (iii) the migration of belts following apparent path of the sun; (iv) the distribution of continents and oceans; (v) the rotation of earth. The pattern of the movement of the planetary winds is called the general circulation of the atmosphere.

Solution: c)

NCERT Class XI, Fundamentals of Physical Geography, Page – 92

During El Nino, fishing declines in the Eastern Pacific as there is an absence of upwelling of cold water which brings rich nutrients.

http://www.pmel.noaa.gov/elnino/what-is-el-nino

Solution: b)

NCERT Class XI, Fundamentals of Physical Geography, Page – 95

Note the word precisely in statement – 1.

Strongest winds are located in the wall next to eye.

The eye is a region of calm with subsiding air. Around the eye is the eye wall, where there is a strong spiralling ascent of air to greater height reaching the tropopause. The wind reaches maximum velocity in this region, reaching as high as 250 km per hour.

http://www.nhc.noaa.gov/aboutgloss.shtml

Solution: b)

NCERT Class XI, Fundamentals of Physical Geography, Page – 100

Sleet is frozen raindrops and refrozen melted snow-water. When a layer of air with the temperature above freezing point overlies a subfreezing layer near the ground, precipitation takes place in the form of sleet. Raindrops, which leave the warmer air, encounter the colder air below. As a result, they solidify and reach the ground as small pellets of ice not bigger than the raindrops from which they are formed. Sometimes, drops of rain after being released by the clouds become solidified into small rounded solid pieces of ice and which reach the surface of the earth are called hailstones. These are formed by the rainwater passing through the colder layers. Hailstones have several concentric layers of ice one over the other.

Solution: b)

NCERT Class XI, Fundamentals of Physical Geography, Page – 105

https://en.wikipedia.org/wiki/Climate_of_Los_Angeles

Solution: b)

NCERT Class XI, Fundamentals of Physical Geography, Page – 115

https://www.britannica.com/science/guyot

Solution: b)

NCERT Class XI, Fundamentals of Physical Geography, Page – 118

The North Sea, in spite of its location in higher latitudes, records higher salinity due to more saline water brought by the North Atlantic Drift. Baltic Sea records low salinity due to influx of river waters in large quantity. The Mediterranean Sea records higher salinity due to high evaporation. Salinity is, however, very low in Black Sea due to enormous fresh water influx by rivers. See the atlas to find out the rivers joining Black Sea. The average salinity of the Indian Ocean is 35 o/oo. The low salinity trend is observed in the Bay of Bengal due to influx of river water by the river Ganga. On the contrary, the Arabian Sea shows higher salinity due to high evaporation and low influx of fresh water.