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General Science MCQ Practice
Practice General Science questions with instant scoring, correct answer highlighting, detailed solutions and first-click AI explanation caching for missing explanations.
📚 Questions: 553
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Q. 3776
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The first nuclear test conducted by India under the code name of "Smiling Buddha" was in the year:
Correct option: B (1974)
- Why this is correct: India's first nuclear test, code-named “Smiling Buddha,” was conducted in 1974 at Pokhran.
- Key concept: Peaceful Nuclear Explosion to demonstrate capability; marks entry into nuclear club.
- Brief numeric note: Yearly date is 1974; no yield focus needed for basic memory.
- Why others are incorrect: 1973, 1975, 1976 are not the year of the Pokhran test.
- Exam tip: Remember 1974 as the year of India’s first test; 1998 is later for multiple tests.
Q. 3772
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A device that is responsible for changing the voltage is:
- Correct option: A. Transformer
- Reason: A transformer uses electromagnetic induction between primary and secondary coils to change AC voltage. The voltage ratio follows Vp/Vs = Np/Ns, where N is the number of turns.
- Key concept: Mutual induction and turns ratio control voltage change.
- Exam tip: Remember "Vp/Vs = Np/Ns" for voltage change (not power if ideal).
- Why others are incorrect: Encoder/Decoder/Translator are communication devices, not voltage-changing devices.
Q. 3771
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In which year was the "@" chosen for its use in e-mail addresses?
Answer: A) 1972
- Why correct: Ray Tomlinson chose the "@" symbol to separate the user name from the host in electronic mail addresses in 1972.
- Key concept: The "@" acts as a delimiter in email addressing, linking user and domain.
- Brief logic: This established the standard format user@host.
- Exam tip: Remember early internet milestones (ARPANET) for such questions.
- Why others are incorrect: 1976, 1980, 1984 relate to later standards and developments, not the original choice.
Q. 3768
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Plants absorb dissolved nitrates from soil and convert them into:
Correct answer: C) ammonia
- Key concept: Nitrogen assimilation. Plants take up nitrate (NO3−) and reduce it to ammonium (NH4+), often called ammonia, which is then used to synthesize amino acids and proteins.
- Process: NO3− → NO2− (nitrate reductase) → NH4+ (nitrite reductase) → amino acids.
- Why others are incorrect:
- A) free nitrogen (N2) is not taken up by most plants.
- B) urea is not the direct product of nitrate reduction in plants.
- D) proteins are synthesized from amino acids, not directly from nitrates.
- Exam tip: Remember “nitrate → ammonium → amino acids” as the main nitrogen assimilation pathway.
Q. 3764
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India's first atomic power station was set up at:
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Q. 3763
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Which of the following is a non metal that remains liquid at room temperature?
Answer: B
- Reason: Bromine (Br2) is a halogen that is a liquid at room temperature, melting at about -7.2°C and boiling at 58.8°C.
- Key concept: Non-metals can be solids, liquids, or gases at RT; halogens include F2, Cl2, Br2, I2 with Br2 being the only liquid at room temperature.
- Why others are incorrect: Phosphorus is a solid, Chlorine is a gas, Helium is a gas at RT.
- Exam tip: Remember diatomic molecules; bromine is the only liquid among common non-metal elements at room temperature.
Q. 3762
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One kilometre is equal to how many miles?
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Q. 3761
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Which type of fire extinguisher is used for petroleum fire?
Correct answer: A
- Why: Dry chemical powder interrupts the chemical reactions occurring in the flame and forms a crust over the liquid, isolating fuel from oxygen. This makes it effective for petroleum (Class B) fires.
- Key concept: For flammable liquids, extinguishing agents must prevent ignition and chemical reactions; powder achieves this well.
- Other options: Foam (D) and other liquids are also used for Class B, but the given correct choice is powder here. Soda-acid (C) is outdated and unsafe; plain powder is preferred for many petroleum fires.
- Exam tip: Do not use water on oil/gas fires; use appropriate non-water-based extinguishers.
Q. 3760
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The hottest part of the gas flame is known as:
Explanation
- The non-luminous zone of a gas flame is the blue part, where combustion is most complete and temperatures are highest.
- Luminous zone glows yellow/orange due to incandescent soot and is cooler.
- Key concept: flame temperature varies with soot formation; complete combustion yields a hotter, blue flame.
- Tip: Remember—yellow (luminous) = cooler; blue (non-luminous) = hotter.
Q. 3755
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The salinity of the sea water is:
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