BPSC CCE Prelims
General Science Previous Year Questions (PYQs)
Solved Previous Year Questions (PYQs) for General Science in BPSC CCE Prelims in English & Hindi Medium.
Chapter Breakdown: Scroll →
Chlorophyll absorbs _________ wavelengths of the sunlight.
Detailed Explanation:
Chlorophyll is the green pigment in plants that absorbs red and blue wavelengths of sunlight most effectively for photosynthesis.
Green light is reflected (not absorbed), which is why plants appear green to our eyes.
Which of the following is not a correct match?
Detailed Explanation:
✅ Statement 1 – Correct: Petiole is the stalk that attaches the leaf blade to the stem.
❌ Statement 2 – Incorrect: Trees have thick, hard stems with branching near the top, not near the base; shrubs have branching near the base.
✅ Statement 3 – Correct: Creepers have weak stems that cannot stand upright and grow along the ground (e.g., pumpkin, watermelon).
Water reaches great heights in trees because of suction pull caused by
Detailed Explanation:
Transpiration is the primary mechanism responsible for the upward movement of water in tall trees.
Transpiration creates a negative pressure (suction pull) at the top of the plant as water evaporates from leaf stomata, pulling the entire water column upward through xylem vessels via cohesion-tension theory.
While evaporation occurs from leaf surfaces, it is specifically the transpiration process (evaporation through stomata) that generates the pulling force; absorption by roots is passive and responds to this pull rather than creating it.
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Which among the following is a character of chloroplast which makes them qualified to self-replication?
Detailed Explanation:
Chloroplasts are semi-autonomous organelles capable of self-replication because they contain their own genetic material – both circular DNA (similar to prokaryotes) and RNA (including ribosomal RNA, transfer RNA, and messenger RNA).
The presence of both DNA and RNA enables chloroplasts to synthesize their own proteins and replicate independently within the cell, a characteristic shared with mitochondria that supports the endosymbiotic theory of their evolutionary origin.
What type of lens is used in magnifying glass?
Detailed Explanation:
A convex lens is thicker at the center and converges light rays. When an object is placed between the lens and its focal point, it produces a magnified, upright, virtual image—the principle behind magnifying glasses.
Concave lenses and plano-concave lenses diverge light and reduce image size, while convex mirrors also produce diminished images, making them unsuitable for magnification.
Therefore, a convex lens is used in magnifying glasses, making Option 2 the correct answer.
The paramagnetic theory of magnetism applies to
Detailed Explanation:
Paramagnetic substances are weakly attracted by magnetic fields and have small positive susceptibility (χ > 0). Among the options, platinum is a classic paramagnetic material with unpaired electrons that align weakly with external magnetic fields.
Iron and nickel are ferromagnetic (strongly magnetic, χ >> 1000), while mercury is diamagnetic (weakly repelled, χ < 0). Other paramagnetic examples include aluminium and manganese.
Therefore, only platinum exhibits paramagnetic behavior, making Option 3 the correct answer.
The nucleus of an atom consists of
Detailed Explanation:
The nucleus of an atom contains protons (positively charged) and neutrons (neutral), forming the dense central core discovered by Rutherford in 1911.
Electrons orbit outside the nucleus in electron clouds—they are not part of the nuclear structure.
Therefore, only protons and neutrons constitute the nucleus, making Option 2 the correct answer.
The metallurgical process in which a metal is obtained in a fused state is called
Detailed Explanation:
Smelting is the metallurgical process where ore is heated with a reducing agent (like coke) to extract the metal in a fused (molten) state, separated from slag.
Roasting converts sulfides to oxides in excess air, calcination removes volatile impurities in limited air, and froth flotation is a physical concentration method—none produce molten metal directly.
Therefore, only smelting yields metal in a fused state, making Option 4 the correct answer.
Which among the following are constituents of brass?
Detailed Explanation:
Brass is an alloy composed primarily of copper (Cu) and zinc (Zn). The proportion of these two metals can vary (typically 55–95% copper, 5–45% zinc), affecting properties like color, hardness, and corrosion resistance.
Other options are incorrect: Iron and zinc do not form brass; copper and nickel form cupronickel; iron and copper is not a standard brass alloy.
Therefore, zinc and copper are the constituents of brass, making Option 4 the correct answer.
Which among the following is known as quicklime?
Detailed Explanation:
Quicklime is the common name for calcium oxide (CaO), produced by heating limestone (CaCO₃) to drive off carbon dioxide.
Ca(OH)₂ is slaked lime (formed when quicklime reacts with water), CaCl₂ is calcium chloride, and CaCO₂ is not a valid chemical formula.
Therefore, CaO is quicklime, making Option 4 the correct answer.
What happens to the weight of iron, when it rusts?
Detailed Explanation:
Rusting is oxidation of iron (4Fe + 3O₂ → 2Fe₂O₃·xH₂O), where oxygen and water molecules bond to iron atoms, increasing total mass as hydrated iron oxide forms.
Over time, the rust layer flakes off or detaches from the surface due to its brittle nature, causing the overall weight to decrease.
Therefore, the weight first increases (oxidation) then decreases (flaking), making Option 2 the correct answer.
Which among the following is also known as white metal?
Detailed Explanation:
Platinum is a lustrous, dense, silver-white precious metal with high corrosion resistance and catalytic properties. It is commonly referred to as white metal due to its natural silvery-white appearance.
Gold is yellow, copper is reddish-brown, and cobalt is greyish-blue—none match the white metal descriptor. While industrial alloys of tin/lead are sometimes called "white metal," in UPSC/general knowledge context, platinum is the standard answer.
Therefore, platinum's silvery-white color makes Option 2 the correct answer.
Consider the following statements with respect to noble metals :
- Noble metals are found in pure form in nature.
- Uranium and lead are examples of noble metal.
Which of the above statements is/are correct?
Detailed Explanation:
Noble metals (gold, silver, platinum, and platinum-group metals) are chemically inert, resist corrosion, and are typically found in pure native form in nature due to their nonreactive properties.
- Statement 1 is Correct: Noble metals like gold and platinum occur naturally in uncombined, pure metallic state.
- Statement 2 is Incorrect: Uranium and lead are highly reactive metals that occur as ores (e.g., uraninite, galena), not as noble metals.
- Therefore, only Statement 1 is correct, making Option 4 the correct answer.
Consider the following statements :
- Addition of salt to pure water increases the boiling point of water and decreases the freezing point of water.
- When methyl alcohol is added to water boiling point of water decreases.
Which of the above statements is/are correct?
Detailed Explanation:
Salt (NaCl) is a non-volatile solute that causes boiling point elevation and freezing point depression through colligative properties—saltwater boils at a higher temperature and freezes at a lower temperature than pure water.
Methyl alcohol (methanol) is a volatile solute with higher vapor pressure than water. When added to water, it increases the overall vapor pressure of the mixture, causing the boiling point to decrease.
Therefore, both statements correctly describe opposite effects due to different solute types, making Option 3 the correct answer.
Which among the following is the main constituent of biogas?
Detailed Explanation:
Biogas is produced by anaerobic digestion of organic matter and contains 50–70% methane (CH₄), which is its primary combustible component.
Propane, butane, and ethane are constituents of petroleum gas and natural gas, not biogas.
Therefore, methane is the main constituent of biogas, making Option 4 the correct answer.