DAILY CURRENT AFFAIRS QUIZ – 30 November 2024

Ans: b) Rossby waves

Explanation: Twin cyclones originate from the interaction of wind systems, monsoon patterns, and Earth’s dynamics through the formation of equatorial Rossby waves, which are massive ocean waves with long wavelengths that can span thousands of kilometers.

Explanation:

Radio waves, the electromagnetic spectrum’s longest wavelengths, vary from the size of a football to exceeding the dimensions of our planet. Within the ionosphere, an abundance of free electrons exists. When High Frequency (HF) radio waves, possessing frequencies below the ionosphere’s critical frequency, encounter these free electrons, they prompt electron vibrations. Consequently, these vibrating electrons emit the energy back down at the same frequency.

Therefore, it’s not solely the length of the wavelength or its shortness that holds significance. Instead, the wavelength, which is inversely tied to the frequency of the wave, must fall within an appropriate range for the waves to undergo reflection by the ionosphere.

Ans. c

Explanation:

The Inter-Tropical Convergence Zone (ITCZ):

1. Geographical Position and Nature

• Geographical Range: Extending approximately five degrees north and south of the equator, the ITCZ forms a broad belt encircling the Earth.
• Pressure Characteristics: It represents a wide trough of low pressure situated in equatorial latitudes, where the northeast and southeast trade winds converge.

2. ITCZ Movement and Seasonal Impact

• Movement in Relation to the Equator: ITCZ generally aligns parallel to the equator but shifts its position northward or southward following the apparent movement of the sun.
• Seasonal Influence on Rainfall: Shifts in the ITCZ significantly impact rainfall patterns in equatorial regions, leading to distinct wet and dry seasons characteristic of the tropics, different from the cold and warm seasons found in higher latitudes.

3. Comparison of ITCZ Shifts between Hemispheres

• Northern vs. Southern Hemisphere Shifts: The movement of the ITCZ exhibits a lesser shift in the Southern Hemisphere compared to the Northern Hemisphere. This is primarily due to the more continental nature of the Northern Hemisphere, resulting in a sharper temperature gradient.

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:

Geostrophic Wind:

1. Concept of Geostrophic Wind

• Definition: Geostrophic wind emerges from the precise equilibrium between the Coriolis force and the pressure gradient force within atmospheric science.
• Geostrophic Equilibrium: This state, known as geostrophic equilibrium or balance, signifies the condition where the geostrophic wind develops.

2. Direction and Relation to Isobars

• Geostrophic Wind Direction: It flows parallel to the isobars, representing lines of constant pressure.
• Natural Variances: Geostrophic balance rarely remains exact in nature due to additional forces like ground friction.

3. Differences from True Wind

• True Wind vs. Geostrophic Wind: Actual winds typically deviate from the geostrophic wind due to factors such as ground-based friction.
• Conditions for Equality: The actual wind would mirror the geostrophic wind solely in the absence of friction, for instance, above the atmospheric boundary layer, and in the scenario of perfectly straight isobars.