Day-658 | Daily MCQs | UPSC Prelims | GEOGRAPHY

Answer: B
Explanation: Both Statement-I and Statement-II are correct and Statement-II is not the correct explanation for Statement-I
Statement-I is correct:
Factors affecting Temperature Distribution in the oceans-
● The factors which affect the distribution of temperature of ocean water are:
⮚ Latitude
⮚ Prevailing wind
⮚ Ocean currents
⮚ Unequal distribution of land and water
⮚ Continentality
● All these factors influence the temperature of the ocean currents locally.
● The enclosed seas in the low latitudes record relatively higher temperatures than the open seas:
➢ The main reason for this phenomenon is the effect of continentality.
➢ Since the specific heat of continents is lower than that of oceans, the rate of cooling and heating of continents is higher than the water bodies. As the regions of lower latitudes receive a good amount of insolation, the enclosed seas are able to absorb more heat from the surrounding land. This makes the closed seas having higher temperature as compared to the open seas of the same latitudes.
➢ Moreover, enclosed seas are typically surrounded by land masses on most sides, which limits water exchange with the open ocean. This isolation can lead to reduced water movement, making it easier for heat to accumulate in the enclosed sea.
❖ Example – Mediterranean Sea, Red Sea
● whereas the enclosed seas in the high latitudes have lower temperatures than the open seas.
❖ The warming effect of the warm ocean currents seems to be the most pertinent reason for this effect in seas of higher latitudes.
➢ Enclosed seas in high latitudes often have limited exchange with warmer ocean currents. This geographical isolation can lead to slower heat transfer from other parts of the ocean, resulting in cooler temperatures.
➢ Example – Open seas at high latitudes, like the North Atlantic, can be influenced by warm ocean currents (e.g., the Gulf Stream), which carry warmer water from lower latitudes, raising their temperatures. Enclosed seas like the Baltic Sea due to their geographic barriers, don’t benefit from such warm currents.
Statement-II is correct but not an explanation for statement 1:
● Enclosed seas in low latitudes tend to experience more evaporation due to a combination of several factors like high temperatures, longer daylight hours, high humidity, limited freshwater input, and stable atmospheric conditions in low-latitude regions contribute to higher evaporation rates in enclosed seas located in these areas.
● This is the reason that the enclosed seas of low latitudes have more salinity than the open seas in the same latitudes.
● Example – Red Sea, Dead Sea etc.

Answer: A
Explanation: Both Statement-I and Statement-II are correct and Statement-II is the correct explanation for Statement-I
Lava:
● Magma is an extremely hot liquid and semi-liquid rock located under Earth’s surface. When magma flows onto Earth’s surface, it is called lava.
Types of lava:
● There are three basic types of magma: basaltic, andesitic, and rhyolitic, each of which has a different mineral composition.
The colour of lava is closely related to its composition, particularly the presence of silica (SiO2) content. The silica content influences the colour of lava as follows:
Andesitic Lava: There is a higher amount of silica in this type of lava.
● Color: Andesitic lava has a higher amount of silica content; it therefore appears light colored when solidified.
● These lavas are highly viscous with a high melting point.
● Andesitic lava is commonly associated with stratovolcanoes at convergent plate boundaries.

Answer: B
Explanation: Only Statement 2 is correct
Statement 1 is incorrect:
Magnetic Declination:
● Magnetic declination, also known as magnetic variation, is the angle between magnetic north (the direction a compass needle points) and true north (the direction towards the geographic North Pole).
⮚ Magnetic Poles: The magnetic poles refer to the points on the Earth’s surface where the magnetic field lines appear to converge and enter or emerge.
⮚ Geographical north: It is also known as true north, refers to the direction towards the geographic North Pole, which is the northernmost point on the Earth’s surface.
o It is aligned with the Earth’s axis of rotation, which extends from the geographic North Pole to the geographic South Pole.
o Unlike magnetic north, which is determined by the Earth’s magnetic field and can vary based on location and time, geographical north remains relatively constant and is the reference point for navigation and mapping purposes.
● In simpler terms, it’s the angular difference between the direction a compass points and the direction of the earth’s axis.
● Declination is positive when this angle is east of true north and negative when it is west.
● Magnetic declination changes over time, and with location.
Statement 2 is correct:
● Declination value is needed to determine true north, because compasses point toward magnetic north.
● By knowing the magnetic declination for their location, sailors can adjust their compass readings to compensate for the difference between magnetic north and true north.
⮚ Example – If the magnetic declination is known to be 10 degrees east, the sailors can correct their compass readings by subtracting 10 degrees from the indicated magnetic direction. With this correction, the ship can maintain a true north heading, aligning with the intended route.

Answer: B
Explanation: River Kali Sindh and River Kuno are the tributaries of the Chambal river.
Yamuna River:
The Yamuna is the largest and the most important tributary of the Ganga. It originates from the Yamunotri glacier on the Bandarpunch Peak in Garhwal in Uttarakhand.
The tributaries of the Yamuna:
● The main tributary of Yamuna in its upper reaches is the Tons which also rises from the Bandarpunch glacier and joins Yamuna at Kalsi near Dehradun.
● The Yamuna receives some important tributaries originating from the peninsular plateau which are-
⮚ The Chambal, the Sindh, the Betwa and the Ken.

Answer: C
Explanation: The Hawaiian Islands are more of a type of Volcanic islands.
Convergent Boundaries:
● A convergent boundary is an area on earth where two or more lithospheric plates collide with each other.
● Convergent boundaries are of three types, depending on the type of crust present on either side of the boundary — oceanic or continental.
⮚ The types are ocean-ocean, ocean-continent, and continent-continent.
● At convergent plate boundaries, oceanic crust is often forced down into the mantle where it begins to melt.
● Magma rises into and through the other plate, solidifying into granite, the rock that makes up the continents.
● Thus, at convergent boundaries, continental crust is created and oceanic crust is destroyed.
● This can give rise to large land masses like in the case of the formation of island masses of the Philippines, the Indonesian islands and the Caribbean islands.
The formation of the Philippines Islands:
● The Philippine Island system is formed due to subduction of the Philippine Sea plate under the Sunda Plate.