DAILY CURRENT AFFAIRS QUIZ – 16 November 2024

Ans. b

Explanation:

Vertical Pressure Gradient and Atmospheric Dynamics:

1. Vertical vs. Horizontal Pressure Gradients

• Vertical Pressure Gradient: Significantly larger than horizontal pressure gradient but typically counterbalanced by an almost equal, opposing gravitational force. As a result, strong upward winds are generally absent.

2. Pressure Variations with Height

• Vertical Pressure Gradient or Variation: In the lower atmosphere, pressure diminishes swiftly with altitude. This vertical pressure variation, often known as the vertical pressure gradient, decreases at an approximate rate of 34 millibars for every 300 meters in height.

3. Pressure-Driven Air Motion

• Cause of Air Motion: Atmospheric pressure variances drive air movement, leading winds to flow from areas of high pressure toward regions of low pressure.

4. Pressure Changes and Weather Indicators

• Weather Indicators: Rising pressure signifies stable, clear weather conditions, while falling pressure indicates potential instability and cloudy weather.

5. Pressure Variability and Altitude

• Altitude and Pressure Relations: At higher elevations, such as at the summit of Mt. Everest, air pressure is significantly lower, approximately two-thirds less than at sea level.
• Variable Factors Affecting Pressure: Pressure decrease with altitude isn’t constant due to changing factors influencing air density—temperature, water vapor content, and gravity. This variability prevents a simple, direct relationship between altitude and pressure.

6. Gravity, Density, and Pressure

• Gravity’s Influence on Pressure: At the surface, denser air due to gravity results in higher pressure. As air pressure is contingent on both density and temperature, alterations in either temperature or density bring about corresponding pressure changes.

Ans. a

Explanation:

Heating and Cooling Processes in the Atmosphere:

1. Heat Transmission Mechanisms

• Overview: Various methods exist for heating and cooling the atmosphere. After absorbing solar radiation (insolation), the Earth emits heat to the nearby atmospheric layers in the form of long waves.

2. Convection for Vertical Heating

• Statement 1 (Correct): Vertical heating of the atmosphere occurs through convection. As the air adjacent to the Earth’s surface warms, it ascends vertically in currents, transferring heat throughout the atmosphere. This process is primarily limited to the troposphere.

3. Conduction’s Role in Lower Atmosphere Heating

• Statement 2 (Correct): Conduction occurs when land-contacting air gradually heats up, transmitting warmth to upper layers. This process involves energy transfer between bodies of different temperatures in direct contact, where heat flows from warmer to cooler bodies. Conduction significantly contributes to heating the lower atmospheric layers.

4. Horizontal Heat Transfer: Advection

• Statement 3 (Incorrect): Heat transfer through the horizontal movement of air is termed advection. Contrary to the statement, in some cases, horizontal movement of air is more influential than vertical movement.

5. Impact on Daily Weather Variations

• Middle Latitudes and Daily Variation: Daily weather variations, especially in middle latitudes, are predominantly caused by advection alone, not by vertical movements. For instance, the ‘loo’ winds in northern India during summer are a result of the advection process in tropical regions.

Ans. a

Explanation:

Cumulonimbus Cloud Characteristics:

1. Cloud Structure and Height

• Description: Cumulonimbus clouds stretch extensively upwards in towers or plumes, commonly recognized as thunderclouds due to their unique ability to generate hail, thunder, and lightning.

2. Distinctive Features

• Appearance: These clouds typically exhibit a flat base, accompanied by a dark, wall-shaped structure hanging beneath. The cloud base might be positioned just a few hundred feet above the Earth’s surface.

3. Formation and Convection

• Origin and Development: Cumulonimbus clouds originate from convection processes. They can also form along cold fronts, specifically due to forced convection, where warmer air is compelled to ascend over incoming cold air masses.

Ans. d

Explanation:

Distinctions Between Fogs and Mists:

1. Clarification on Fogs and Mists Moisture Content

• Statement 1 (Incorrect): Contrary to the statement, fogs are not drier than mists. Both fogs and mists, which are ground-level clouds, form when water condenses around particles in a substantial mass of air close to the Earth’s surface. However, mist typically contains higher moisture content. This occurs because each nucleus in mist retains a thicker layer of moisture around it compared to fog.

2. Formation and Circumstances

• Statement 2 (Incorrect): Fogs primarily occur when warm air currents intersect with colder currents. In contrast, mists usually form in mountainous areas where ascending warm air encounters a cold surface.

Ans. c

Explanation:

Annual Temperature Range Variations:

1. Definition of Annual Range

• Description: The annual range represents the difference between the warmest and coldest months, determined by averaging monthly temperatures.
• Statement 1 (Correct): Maximum annual range is observed notably across the vast interiors of continents in the Northern Hemisphere, prominently evident over regions like the Siberian Plains.
  • Continentality Effect: Land heats and cools rapidly compared to water due to differences in specific heat capacity. This leads to substantial temperature variations across seasons, notably pronounced over landmasses compared to oceans.
  • Northern Hemisphere Dynamics: With more landmass, the Northern Hemisphere interior (like the Siberian Plains) exhibits the most significant annual temperature range due to these variations, whereas the Northern Atlantic, influenced by warm ocean currents, shows a narrower range due to moderated temperatures.

2. Lowest Annual Range near the Equator

• Statement 2 (Correct): Regions within a narrow equatorial belt (approximately between 20 degrees South and 15 degrees North) experience the smallest annual temperature range, averaging around 3 degrees Celsius.
  • Equatorial Conditions: Proximity to the Equator results in nearly uniform insolation and consistent weather throughout the year, leading to minimal fluctuations in temperature. Consequently, these areas lack extremes of both hot and cold, hence exhibiting very low annual temperature ranges.