Natural Disasters
7 solved SSC CGL Science previous year questions on Natural Disasters, each with the correct answer and a full explanation.
Q1
The minimum short-term natural hazard is __________ .
✓ Correct answer: d) bolt of lightning
ExplanationA bolt of lightning is a short-duration natural hazard that occurs instantly and lasts for a very brief period, typically measured in milliseconds.Blizzard: Can last several hours to days.Earthquake: Lasts from a few seconds to minutes but may have long-term aftershocks.Volcanic eruption: Can persist for hours, days, or even longer.Hence, the correct answer is "bolt of lightning".
Q2
What is the name of the tropical cyclones in the China Sea?
✓ Correct answer: d) Typhoon
ExplanationTropical cyclone is a rapidly rotating storm with a low-pressure center, strong winds, and a closed low-level atmospheric circulation.It is a spiral thunderstorm that causes heavy rain in the area.Typhoons are tropical cyclones in the China Sea.Willy- Willy Australia Hurrica ne Atlantic Ocean(USA) Typhoo n South China Sea and Western Pacific Ocean Hence, the correct answer is “Typhoon”.
Q3
Tsunami is caused by ______.
✓ Correct answer: a) underwater volcanic activity
ExplanationTsunamis are large ocean waves that are primarily caused by underwater seismic activity, such as earthquakes.When an earthquake occurs beneath the ocean floor, it can result in the sudden vertical displacement of the water column above.This displacement generates a series of waves that radiate outwards from the epicenter of the earthquake.As these waves travel through the ocean, they can build up significant energy and momentum.When the waves reach coastal areas, they can unleash their destructive force, causing widespread flooding and devastation.Other factors like volcanic eruptions, landslides, and even meteorite impacts can also trigger tsunamis.Hence, the correct answer is "underwater volcanic activity".
Q4
Which of the following gases is consistently seen to be most abundant in a volcanic eruption?
✓ Correct answer: a) Water vapour
ExplanationThe gas that is consistently seen to be most abundant in a volcanic eruption is water vapor (steam).When magma rises to the surface and erupts, it releases large amounts of steam along with other gases such as carbon dioxide, sulfur dioxide, and hydrogen sulfide.The steam is generated by the rapid heating and expansion of ground or surface water that is present in the volcanic system.The steam acts as a powerful propellant in volcanic eruptions, helping to drive ash, rock fragments, and lava out of the volcano and into the surrounding area.Carbon dioxide (CO2) is a colorless, odorless gas composed of one carbon atom and two oxygen atoms.It is a byproduct of respiration and combustion processes, and is also a key component of the Earth's atmosphere.Sulfur dioxide (SO2) is a colorless gas with a strong, pungent odor.It is produced by the burning of fossil fuels and is also a byproduct of volcanic activity.Hydrogen sulfide (H2S) is a colorless, flammable, toxic gas with a characteristic rotten egg odor.It is produced by the decomposition of organic matter, and is also commonly found in natural gas and petroleum.Hence, the correct answer is "Water vapour".
Q5
An elastic wave generated by an impulse such as an earthquake or an explosion is called _____.
✓ Correct answer: c) Seismic wave
ExplanationA seismic wave is an elastic vibration produced by an impulse like an earthquake or detonation.They are brought on by the Earth's interior elements moving suddenly.The different kinds of seismic waves include: a. P-wave Motion b. S-wave Motion c. Rayleigh-wave Motion d. Love-wave Motion The pattern of disturbance caused by energy moving through a material is known as a sound wave.The shifting of the continents that make up the structure of the Earth is known as a tectonic shift.The epicenter, or spot above the focus on the Earth's surface, is the location from which an earthquake's waves propagate.Hence, the correct answer is "Seismic Wave".
Q6
In the context of India, tropical cyclones originate over the _________
✓ Correct answer: c) Bay of Bengal
ExplanationThe Bay of Bengal and the Indian Ocean are the birthplaces of tropical cyclones.The coasts of Tamil Nadu, Andhra Pradesh, and Orissa are all affected by these tropical cyclones, which have very high wind speeds and produce significant rainfall.The widespread low pressure that is caused by the warm water in the ocean is likely to blame for the cyclones that occur in the Bay of Bengal.Hence, the correct answer is "C) Bay of Bengal ."
Q7
Which of the following is NOT a broad mitigation technique of landslide?
✓ Correct answer: c) Reduction in the vegetation cover to arrest landslide
ExplanationDecreasing vegetation cover to arrest landslides is NOT correct among the mechanisms of landslides mitigation.Landslides Mitigation Mechanisms: Hazard mapping to identify areas prone to landslides.Construction of retention walls to stop land slippage.Increasing vegetation cover to arrest landslides.Ensuring surface drainage control works to restrict the movement of landslides.Hence, the correct answer is "Reduction in the vegetation cover to arrest landslide."
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