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Class 9 (1226 questions)
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by GIANSH GUPTA KHUNDKER
· Class 9
Which type of electromagnetic wave has a wavelength shorter than visible light but longer than X-rays, and is commonly used for sterilizing medical equipment?A) Infrared radiationB) MicrowavesC) Ultraviolet radiationD) Gamma rays
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by GIANSH GUPTA KHUNDKER
· Class 9
Two resistors, one with a resistance of 3.0 Ω and another with a resistance of 6.0 Ω, are connected in parallel across a 12 V battery. What is the total current drawn from the battery by this parallel combination?A) 1.3 AB) 4.0 AC) 6.0 AD) 9.0 A
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by GIANSH GUPTA KHUNDKER
· Class 9
A student stands 165 meters away from a tall vertical wall and claps their hands loudly. If the speed of sound in air is 330 m/s, how much time elapses between the clap and the student hearing the echo?A) 0.5 secondsB) 1.0 secondC) 1.5 secondsD) 2.0 seconds
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by GIANSH GUPTA KHUNDKER
· Class 9
A uniform meter rule is balanced horizontally at its midpoint pivot (the 50 cm mark). A 4.0 N weight is suspended from the 20 cm mark. What force must be applied downward at the 90 cm mark to maintain horizontal equilibrium?A) 2.0 NB) 3.0 NC) 4.0 ND) 6.0 N
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by GIANSH GUPTA KHUNDKER
· Class 9
Which domestic water conservation strategy focuses on reducing the demand for treated potable (drinking) water by utilizing household wastewater from sinks, showers, and washing machines for garden irrigation?A) Rainwater harvesting from rooftopsB) Recycling greywaterC) Desalination of domestic groundwaterD) Blackwater purification systems
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by GIANSH GUPTA KHUNDKER
· Class 9
An astronaut transports a rock sample with a mass of 3.0 kg from Earth to the Moon. The gravitational field strength on Earth is 10 N/kg, and on the Moon, it is 1.6 N/kg. What are the mass and weight of the rock on the Moon?A) Mass = 0.48 kg, Weight = 4.8 NB) Mass = 3.0 kg, Weight = 30 NC) Mass = 3.0 kg, Weight = 4.8 ND) Mass = 0.48 kg, Weight = 30 N
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by GIANSH GUPTA KHUNDKER
· Class 9
A cargo ship is caught transporting illegally harvested elephant ivory across international borders. Which international agreement is designed to ban the trade of endangered species and their products?A) The Kyoto ProtocolB) CITES (Convention on International Trade in Endangered Species)C) The Montreal ProtocolD) MARPOL Convention
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by GIANSH GUPTA KHUNDKER
· Class 9
Which of the following is a direct atmospheric consequence of large-scale deforestation in the Amazon basin?A) Increased oxygen production due to fewer decaying plants.B) Decreased regional temperatures due to higher albedo.C) Reduced transpiration leading to decreased local rainfall and prolonged droughts.D) Rapid increase in stratospheric ozone concentrations.
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by GIANSH GUPTA KHUNDKER
· Class 9
A logging company operates in a tropical rainforest. To harvest timber sustainably without causing massive soil erosion or destroying the entire ecosystem, which management strategy should they use?A) Clear-cutting the entire forest areaB) Selective logging of mature treesC) Slash-and-burn cultivationD) Extensive monoculture replanting
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by GIANSH GUPTA KHUNDKER
· Class 9
To prevent the collapse of a specific marine fishery due to overfishing, a government introduces a "quota system." What does this mean?A) Ban all commercial fishing vessels from entering the ocean indefinitely.B) Set a legally enforceable limit on the maximum weight of fish that can be caught.C) Change the legal mesh size of the nets to ensure no small fish escape.D) Increase financial subsidies to help fishermen buy bigger boats.
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by GIANSH GUPTA KHUNDKER
· Class 9
A rural village experiences a sudden outbreak of cholera. Medical investigators trace the source back to a local well contaminated by overflowing sewage. How is cholera scientifically classified?A) A vector-borne disease spread by mosquitoes.B) A water-borne disease caused by ingesting pathogenic bacteria.C) A nutritional deficiency disease caused by lack of clean proteins.D) A water-washed disease caused by insufficient personal hygiene.
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by GIANSH GUPTA KHUNDKER
· Class 9
An industrial plant discharges small amounts of a persistent heavy metal (mercury) into a river. Over time, predatory fish at the top of the river's food chain accumulate lethal levels of mercury in their tissues. What are the dual processes driving this phenomenon?A) Eutrophication and subsequent deoxygenation.B) Leaching and surface runoff.C) Bioaccumulation within individuals and biomagnification up the food chain.D) Nitrification and nitrogen fixation.
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by GIANSH GUPTA KHUNDKER
· Class 9
Which statement accurately describes these countries?A) Country X has a rapidly growing population, while Country Y has a declining population.B) Country X is likely a highly developed country in the final stage of demographic transition.C) Country Y is experiencing a high rate of natural internal population growth.D) Both countries have completely stable populations.
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by GIANSH GUPTA KHUNDKER
· Class 9
Heavy irrigation in an arid climate with high evaporation rates causes water to be drawn up through the soil profile by capillary action. What environmental problem does this create?A) LeachingB) SalinizationC) DesertificationD) Compaction
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by GIANSH GUPTA KHUNDKER
· Class 9
Heavy irrigation in an arid climate with high evaporation rates causes water to be drawn up through the soil profile by capillary action. What environmental problem does this create?A) LeachingB) SalinizationC) DesertificationD) Compaction
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by GIANSH GUPTA KHUNDKER
· Class 9
Which soil conservation technique involves planting crops across a slope following its elevation lines rather than up and down the hill?A) WindbreaksB) Contour ploughingC) MonocultureD) Overgrazing
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by GIANSH GUPTA KHUNDKER
· Class 9
Heavy irrigation in an arid climate with high evaporation rates causes water to be drawn up through the soil profile by capillary action. What environmental problem does this create?A) LeachingB) SalinizationC) DesertificationD) Compaction
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by GIANSH GUPTA KHUNDKER
· Class 9
An environmental scientist wants to estimate the plant species population density across a clearing without introducing bias. Which sampling approach is most appropriate?A) Systematic sampling along a single predetermined transect line.B) Placing quadrats at coordinates chosen by a random number generator.C) Sampling exclusively from areas with thickest vegetation.D) Conducting a single extensive pilot study over one square meter.
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by GIANSH GUPTA KHUNDKER
· Class 9
An island nation faces critical fresh water shortages but has vast access to ocean water. Which process can isolate pure drinking water while leaving behind concentrated brine?A) FlocculationB) SedimentationC) Desalination (via Distillation or Reverse Osmosis)D) Coagulation
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by GIANSH GUPTA KHUNDKER
· Class 9
A country wants to minimize the environmental impact of an abandoned open-pit mine. Which sustainable strategy involves filling the pit with structural waste and covering it with topsoil to restore vegetation?A) BiomagnificationB) Land reclamationC) BioaccumulationD) Deep-well injection
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