Prelims Focus 4th November 2025

Russia’s ‘doomsday missile’

In News: The most recent nuclear submarine built by Russia is ‘Khabarovsk’ that was meant to carry a nuclear underwater drone ‘doomsday missile’.

• ‘Doomsday Missile’ is also referred to as Poseidon and It has the capability to move at great speeds which are more than the current submarines and torpedoes.
• It is capable of working very deep and intercontinentally and this may make intercepting it difficult.
• It can travel to other continents and cause enormous devastation.
• It has the capability to move long distances, in the deep water with nuclear power source. It is able to attack sea targets and become a deterrent.

Auditory Fusion

In News: There are times when two sounds come to your ears so fast that one after the other, that the brain interlocks them and only hears them as one sound. This is referred to as auditory fusion.

• Fusion Threshold is the least time between two sounds that you can tell the difference between them.
• In very short sounds such as clicks, individuals normally require a time interval of 2-3 milliseconds.
• In case more complicated sounds are involved (such as tones, words, or drum beats), the gap needs to be increased – approximately 5-10 or more milliseconds.
• Depending on the degree of loudness of the sounds or the degree of difference in sounds in terms of pitch or tones, the threshold may vary.

India Supports Afghanistan’s Kunar River Dam

In News: India has expressed its support for Afghanistan’s plan to construct a dam on the Kunar River and has reaffirmed its willingness to assist in sustainable water resource management and hydroelectric development.

• The Indian Ministry of External Affairs spokesperson, Randhir Jaiswal, emphasized the history of cooperation between India and Afghanistan on water projects, such as the Salma Dam (officially called the India-Afghanistan Friendship Dam), located in Herat province. 
• India expressed willingness to assist Kabul in hydroelectric projects aimed at addressing Afghanistan’s energy needs and agricultural development.
• This support comes amid rising tensions between Afghanistan and Pakistan, as the Kunar River flows through both countries, with the dam potentially impacting water flow into Pakistan’s northwestern region. 
• Afghanistan’s Supreme Leader under the Taliban regime ordered the construction of dams on the Kunar River “as soon as possible,” with Afghan domestic companies expected to carry out the work.

Madurai Agriculture Boost from Vaigai Dam

In News: The recent timely northeast monsoon rains, coupled with the strategic release of water from the Vaigai Dam, have brought significant relief and optimism to the farmers of Madurai and surrounding areas. 

• Specifically, about 150 cusecs of water have been released into the 58th canal system to irrigate approximately 2,285 acres of agricultural land, including 1,912 acres in the Usilampatti region of Madurai district and 373 acres in Nilakottai of Dindigul district. 
• This water release is critical for paddy cultivation, especially in the double-crop zones where two crops are grown annually.
• The dam’s near-full water level after the monsoon enables sustained irrigation across crucial farming regions, encouraging farmers to commence sowing activities to capitalize on the favorable water conditions. 
• Local officials have emphasized the importance of judicious water use to enhance crop yields and sustainable water management practices to avoid wastage. 
• This intervention helps relieve groundwater stress, improves soil moisture, and supports overall agricultural productivity.
• Farmers have reported a surge in paddy cultivation, with cultivation areas expanding significantly compared to previous years challenged by irregular rainfall. 
• The water release also benefits the rural economy through increased farm labor demand and improved market prospects due to higher crop output. 
• Furthermore, the enhanced irrigation facility prevents excessive runoff, safeguarding water resources for future use.
• The combined effect of northeast monsoon rains and Vaigai Dam water discharge is expected to contribute to a prosperous agricultural season, strengthening food security and farmer livelihoods in the region. 
• Authorities continue to monitor water storage levels and plan phased water releases to maintain a balance between irrigation needs and water conservation through the season

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