General Science MCQ Practice

• Reason: H1N1 is an influenza A virus subtype; infection by H1N1 causes “swine flu” in humans.
• Key concept: Influenza viruses are classified by surface proteins hemagglutinin (H) and neuraminidase (N). H1N1 = H1 and N1.
• Why others are incorrect: Dengue is from dengue virus; AIDS is due to HIV; Bird flu typically refers to H5N1, not H1N1.
• Exam tip: Remember “Swine flu = H1N1” to quickly pick A in similar MCQs.

• Correct option: B — Noise
• Reason: A green muffler is a noise-reduction device attached to vehicles or machinery to lower sound levels, thus tackling noise pollution.
• Key concept: Acoustic damping and energy dissipation reduce sound intensity emitted by engines or machinery.
• Formula/logic (brief): Sound reduction involves decreased sound intensity, often measured in decibels (dB); a muffler reduces dB levels.
• Exam tip: If the option mentions pollution types, choose the one related to sound for devices labeled “muffler.”
• Why others are incorrect: It does not primarily prevent air, soil, or water pollution.

• Why correct: Metals are malleable, meaning they can deform under pressure without breaking, so they can be hammered into sheets.
• Key concept: Metal atoms slide past each other in metallic bonds, allowing layers to rearrange without fracturing.
• Relation to other terms: Ductile = drawn into wires; malleable = hammered into sheets. Do not confuse the two.
• Tip: For sheet formation, remember malleability; for wires, remember ductility.
• Incorrect options: B (not all metals are simply “soft”), D (atomic arrangement is not the reason).

• Why correct: Most insecticides disrupt neural transmission, causing paralysis and death. They often inhibit enzymes (e.g., acetylcholinesterase) or affect sodium channels in nerves.
• Key concept: Nervous system is the primary target because insects rely on rapid nerve signaling for movement and feeding.
• Formula/numbers: Not needed here, but note organophosphates inhibit acetylcholinesterase, increasing acetylcholine and overstimulating nerves.
• Exam tip: If a choice involves paralysis or neural disruption, it likely targets the nervous system.
• Why other options are incorrect: Muscular system is affected downstream; digestive system affects feeding but not primary action; most insecticides do not target only digestion.

• Correct: Nuclear fission — atom bomb uses splitting of heavy nuclei (e.g., U-235) to release huge energy and neutrons, causing a rapid, uncontrolled chain reaction.
• Key concept: mass–energy equivalence (E = Δm c^2) where small mass loss yields large energy; chain reaction sustains explosion.
• Not chemical: chemical bonds release far less energy; bombs rely on nuclear forces, not chemistry.
• Not fusion: fusion powers hydrogen bombs; atom bombs rely on fission.
• Not atomic collision: not the mechanism here.

• Explanation: Only the Stockholm Convention is not about greenhouse gases; it targets persistent organic pollutants.
• Key concept: Kigali Amendment aims to reduce HFCs (a greenhouse gas); Kyoto Protocol sets binding GHG reduction targets.
• Why others are associated with GHG reduction: - Kigali Amendment → phase down HFCs (high global warming potential). - Kyoto Protocol → legally binding GHG emission cuts.
• Exam tip: Remember: Stockholm Convention = POPs, not GHGs.

• Why correct: Pinaka is a Multi Barrel Rocket Launch (MBRL) system developed by India for artillery use, deploying multiple rockets from a single launcher.
• Key concept: MBRL increases firepower and rapid salvo capability; rockets are fired in quick succession from a fixed launch battery.
• Brief note on numbers: Pinaka batteries typically fire a salvo from multiple rockets with ranges around 75 km, improving area saturation.
• Why others are incorrect: It is not an anti-submarine weapon, aircraft carrier, or a submarine frigate warship.
• Exam tip: Memorize the role/platform: MBRL = land-based artillery system, not ships or subs.

• Why correct: Armstrong was the first human to set foot on the Moon during Apollo 11 (1969). He stepped onto the lunar surface first while Buzz Aldrin followed; Michael Collins orbited above in the Command Module.
• Key concept: lunar landing sequence; order matters in human spaceflight events.
• Tip: Remember the famous line “one small step for man, one giant leap for mankind.”
• Why others are incorrect: Aldrin was second on the Moon; Collins did not land on the Moon; Gagarin never reached the Moon (first human in space).

• Key concept: An element is a substance made of only one kind of atom. Marble is not an element; it is a rock/mineral mainly of calcium carbonate (CaCO3), a compound.
• A. Oxygen — element (O)
• B. Nitrogen — element (N)
• C. Hydrogen — element (H)
• Why others are incorrect: A, B, C are pure elements; Marble is a chemical compound/mineral, not a single element.

Exam tip: Remember: elements are listed on the periodic table; rocks/minerals are compounds.

• Concept: A lunar eclipse occurs when the Earth lies directly between the Sun and the Moon, causing Earth’s shadow to fall on the Moon.
• Why correct: This alignment blocks sunlight from reaching the Moon, making it appear dark or reddish.
• Rule/Formula: Sun–Earth–Moon alignment during full Moon phase.
• Why others are wrong: A) would cause a solar eclipse; C) is a solar eclipse; D) is not a real eclipse scenario.
• Exam tip: Remember “Earth in the middle” for lunar eclipses; “Moon in the middle” for solar eclipses.