DAILY CURRENT AFFAIRS QUIZ – 21 November 2024

Ans. c

Explanation:

Factors Influencing Temperature Variations:

1. Location in Relation to the Sea

• Influence on Temperature: A location’s proximity to the sea significantly impacts its temperature. Compared to land, the sea undergoes a slower heating and cooling process, resulting in less temperature variation. Areas near the sea benefit from the moderating effects of sea and land breezes, which help regulate temperature fluctuations.

2. Effects of Air Masses

• Impact on Temperature: Temperature is also influenced by the movement of air masses. Areas affected by warm air masses typically experience higher temperatures, whereas those affected by cold air masses record lower temperatures. Similarly, coastal regions influenced by warm ocean currents exhibit higher temperatures than areas influenced by colder ocean currents along the coastlines.

Ans. c

Explanation:

Temperature Variations in Ocean Depths:

1. Rate of Temperature Decline

• Equatorial versus Polar Regions: Near the equator, the temperature decreases more swiftly with increasing depths compared to the poles. While surface temperatures decline from the equator towards the poles, the temperature at ocean depths remains consistent across this latitudinal range. This discrepancy indicates a more rapid temperature drop with depth near the equator than towards the poles.

2. Temperature Distribution in Oceans

• Surface Temperature Dynamics: The oceans consistently exhibit their highest temperatures at their surfaces. This phenomenon arises due to direct solar heating, wherein the sun’s heat is received at the ocean surface and subsequently transferred downward through the process of convection to lower sections of the oceans.

Ans. b: Inter-Tropical Convergence Zone seldom occurs

Reasons for the Absence of Cyclone Formation in the South Atlantic:

1. Sea Surface Temperatures

• Slightly Cooler Conditions: The sea surface temperatures in the South Atlantic tend to be cooler, falling slightly below the optimal threshold required for the formation of tropical cyclones.

2. Influence of Vertical Wind Shear

• Consistently High Wind Shear: Throughout the year, the South Atlantic experiences notably high vertical wind shear levels. This condition persists even during summer, posing a barrier to cyclone development.

3. Lack of Vorticity and Pre-existing Rotational Centers

• Insufficient Vorticity: The absence of pre-existing rotation centers within the area contributes to the challenge of cyclone genesis. The region typically lacks the necessary vorticity for cyclone formation.

4. Factors Relating to Tropical Waves and ITCZ

• Absence of Tropical Waves: The area lacks the presence of tropical waves, which are vital elements for cyclone initiation.
• Position of the Intertropical Convergence Zone (ITCZ): The ITCZ, shifting with the seasons, typically remains near or north of the equator during the South Atlantic’s summer. This positioning denies the region the critical convergence zone required for cyclone formation.

5. Effect of Strong Wind Shear and ITCZ Position

• Impact of Wind Shear: The South Atlantic experiences strong wind shear in the tropospheric layers, hampering the generation of tropical cyclones.
• ITCZ Positioning Impact: The ITCZ largely remains near the equator, lacking a southward shift over the South Atlantic or South Pacific regions. This absence denies these areas the crucial ITCZ influence, contributing significantly to the lack of cyclones.

6. Additional Factors: Lower Sea Temperatures

• Cooler Sea Temperatures: Lower sea temperatures in these regions further contribute to the lack of conducive conditions for cyclone development.

Important Insight:

• Cyclone Characteristics: Cyclones typically manifest as large wind systems revolving counterclockwise north of the Equator and clockwise to the south.

Ans. c

Explanation:

Jet Streams

• Existence in Both Hemispheres: Jet streams are high-speed air currents present in the upper troposphere. Contrary to Statement 1, they occur in both the Northern and Southern Hemispheres, displaying their influence on global atmospheric circulation.
• Swift and Narrow Belts: These streams manifest as relatively narrow bands of rapid winds, with velocities ranging from 100 km/hr to 900 km/hr. Their narrowness and high speeds distinguish them within the upper troposphere.
• Curved Paths Due to Effects: Their paths follow curved and meandering trajectories primarily because of the Coriolis effect. Additionally, the conservation of angular momentum within large-scale atmospheric systems contributes to their meandering nature.
• Strength of Jet Streams: Jet streams exhibit formidable strength, representing some of the strongest winds in the Earth’s atmosphere.

Tropical Cyclone Formation Conditions

• Warm Sea Surface Temperature: Formation of tropical cyclones necessitates large expanses of warm sea surfaces, typically exceeding 27°C in temperature. These warmer temperatures provide the energy source for their development.
• Coriolis Force and Cyclonic Vortex: The presence of a sufficient Coriolis force is crucial for the creation of a cyclonic vortex, an essential component for tropical cyclone formation.
• Vertical Wind Speed Stability: Minimal fluctuations in the vertical wind speed are necessary to sustain the development of these cyclonic systems.
• Pre-existing Atmospheric Conditions: Prevalence of a weak low-pressure area or a low-level cyclonic circulation acts as a precursor for the formation of tropical cyclones.
• Upper-Level Conditions: A crucial condition involves upper-level divergence above the sea-level system, aiding in sustaining and intensifying the cyclonic formation.

Ans. c

Explanation:

Magnetic Reversals in Earth’s History

1. Historical Reversal Frequency: Experts estimate that magnetic reversals have occurred numerous times within the past three billion years. This recurrence signifies the substantial frequency of these reversals over an extensive period.
2. Recent Reversal Patterns: Over the span of the last 20 million years, the magnetic poles, both north and south, have undergone reversals approximately every 200,000 to 300,000 years. This periodicity indicates a consistent pattern in the recent history of magnetic field fluctuations.
3. Last Major Reversal: The most recent significant magnetic reversal occurred roughly 780,000 years ago, marking a substantial shift in the Earth’s magnetic field during that period.

Composition of Early Atmosphere

1. Early Atmospheric Components: Between 4.5 and 2.5 billion years ago, known as the Archaean and Proterozoic eras, the initial secondary atmosphere consisted of carbon dioxide (CO2), methane (CH4), water vapor (H2O), carbon monoxide (CO), nitrogen (N) in limited quantities, and hydrogen (H). This composition highlights the presence of carbon dioxide within the early atmospheric makeup.
2. Influence of Living Organisms: When life first emerged, it had negligible impact on the composition of the early atmosphere. Contrary to a specific statement, the initial organisms did not significantly alter the composition of the early atmospheric gases. However, according to the official answer key, the correct statements are 1 and 3 only, indicating that the emergence of life did not contribute substantially to altering the early atmosphere.