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RRB JE CBT-1 2025-26 25 February 2026 Shift 3 GK Questions – with answers & solutions

All 29 GK / GS questions asked in RRB JE CBT-1 2025-26 on 25 February 2026 Shift 3, with correct answers and short solutions, subject-wise: Physics, Biology, Chemistry, Current Affairs.

📚 29 questions🗓️ 25 February 2026⏰ Shift 3
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Subjects: Physics (10) · Biology (8) · Chemistry (10) · Current Affairs (1)

Physics (10)

Force and Laws of Motion · Newton's first law and inertia

Q1. A car suddenly changes direction while moving at constant speed. Which aspect of inertia is being demonstrated, and how does the car’s mass influence this effect?

  1. (a) The inertia of speed is demonstrated, and a lighter car resists direction change more.
  2. (b) The inertia of rest is demonstrated, and the car’s mass does not affect direction changes.
  3. (c) Mass only affects speed, not direction, when a car turns.
  4. (d) The inertia of direction is demonstrated, and a car with greater mass will resist the change in direction more.
Answer & solution

Answer: (d) The inertia of direction is demonstrated, and a car with greater mass will resist the change in direction more.

Correct option is 4.
When a car suddenly changes direction, it demonstrates the inertia of direction (a component of inertia related to change in velocity vector).
Inertia resists change in motion direction, not just speed or rest.
A car with greater mass has more inertia, so it resists changes in direction more strongly.
Thus, the heavier the car, the harder it is to change its direction abruptly.
Final answer: Option 4
Light - Reflection and Mirrors · Concave mirror - image formation and uses

Q2. A dentist uses a mirror to obtain a large image of a patient’s tooth. Which mirror should the dentist use and why?

  1. (a) Concave mirror, because it gives a magnified image
  2. (b) Spherical mirror, because it gives a virtual image
  3. (c) Plane mirror, because it gives a real image
  4. (d) Convex mirror, because it gives a magnified image
Answer & solution

Answer: (a) Concave mirror, because it gives a magnified image

The dentist needs a magnified image to examine the tooth details clearly.
Concave mirrors are used because they can form magnified, real or virtual images depending on the object distance.
Specifically, when the tooth is placed between the focal point and the mirror, the concave mirror produces a magnified virtual image, which is ideal for examination.
Other mirrors do not produce a sufficiently magnified image for close detailed work.
Hence, a concave mirror is the correct choice.
Final answer: Option 1
Work, Energy and Power · Kinetic energy

Q3. A student claims that two cars of equal mass, one moving at 40 km/h and another at 80 km/h, have the same kinetic energy if their engines provide the same power. What is the error in this reasoning?

  1. (a) Power supplied determines energy, regardless of speed.
  2. (b) The cars have equal energy if the engines are identical.
  3. (c) Kinetic energy depends on the square of speed, not just on power supplied.
  4. (d) Both cars have equal kinetic energy since both cover the same distance.
Answer & solution

Answer: (c) Kinetic energy depends on the square of speed, not just on power supplied.

Kinetic energy (KE) = 1/2 m v², so it depends on the square of the speed.
Even if engine power is same, KE is not the same for different speeds.
Power relates to rate of doing work, not directly to KE at a given instant.
Therefore, two cars at different speeds have different kinetic energies.
Hence, the error is ignoring that kinetic energy depends on speed squared.
Final answer: Option 3
Light - Refraction and Lenses · Convex lens - image formation and uses

Q4. A student uses a convex lens to project an image of a tree onto a wall. If the image is found to be smaller than the tree, what can be inferred about the tree's position relative to the lens?

  1. (a) The tree is between the lens and its focal point.
  2. (b) The tree is at the focal point of the lens.
  3. (c) The tree is at twice the focal length from the lens.
  4. (d) The tree is placed beyond twice the focal length (beyond 2F) of the lens.
Answer & solution

Answer: (d) The tree is placed beyond twice the focal length (beyond 2F) of the lens.

Solution:
Aconvex lensforms areal, inverted, and diminished (smaller)image when the object is placedbeyond 2F (twice the focal length).
Since the image issmaller than the tree, it must be adiminished image.
Such images are formed only when the object isbeyond 2F.
Hence, the correct answer is:The tree is placed beyond twice the focal length (beyond 2F) of the lens.
Light - Reflection and Mirrors · Convex mirror - image formation and uses

Q5. How do rays parallel to the principal axis behave after reflection from a convex mirror?

  1. (a) They appear to diverge from a point on the principal axis.
  2. (b) They get reflected back along the same path.
  3. (c) They pass through the centre of curvature.
  4. (d) They actually converge at the focus.
Answer & solution

Answer: (a) They appear to diverge from a point on the principal axis.

Rays parallel to the principal axis of a convex mirror reflect in such a way that they appear to diverge.
After reflection, these rays seem to come from the focal point behind the mirror.
Since a convex mirror always forms virtual, erect, and diminished images, the rays do not actually meet but appear to diverge from a virtual focus.
Hence, among the options, the correct behaviour is that rays appear to diverge from a point on the principal axis.
Final answer: Option 1
Gravitation · Numericals on gravitation

Q6. If a body at rest is dropped from a certain height and takes 4 seconds to reach the ground, what is the approximate height from which it was dropped? (Take g = 10 m/s²)

  1. (a) 160 meters
  2. (b) 100 meters
  3. (c) 40 meters
  4. (d) 80 meters
Answer & solution

Answer: (d) 80 meters

When an object is dropped from rest, use the equation of motion for free fall: s =(1)/(2) × g × t²
Given t = 4 seconds and g = 10 m/s², substitute values: s =(1)/(2) × 10 × (4)²
Calculate: s = 5 × 16 = 80 meters
So, the height from which the object was dropped is approximately 80 meters.
Final answer: Option 4
Electricity · Numericals on electricity

Q7. If the current in a wire is 2 amperes, how much charge flows through a cross-section in 5 seconds?

  1. (a) 7 coulombs
  2. (b) 10 coulombs
  3. (c) 2.5 coulombs
  4. (d) 0.4 coulombs
Answer & solution

Answer: (b) 10 coulombs

Current (I) is the rate of flow of charge (Q) through a conductor.
The relation is Q = I × t where,
I = 2 amperes (current)
t = 5 seconds (time)
Calculate charge: Q = 2 × 5
Q = 10 coulombs
So, 10 coulombs of charge flows in 5 seconds.
Final answer: Option 2
Light - Refraction and Lenses · Lens formula and magnification

Q8. What is the sign of the focal length for a convex lens as per the sign convention for spherical lenses?

  1. (a) Positive
  2. (b) Negative
  3. (c) Zero
  4. (d) Variable
Answer & solution

Answer: (a) Positive

For spherical lenses, the sign convention states:
The focal length (f) is positive for a convex lens.
This is because a convex lens converges light rays, hence it has a positive focal length.
Concave lenses have negative focal lengths as per the sign convention.
Therefore, the focal length of a convex lens is positive.
Final answer: Option 1
Light - Reflection and Mirrors · Spherical mirror terminology

Q9. When using the sign convention for spherical mirrors, which direction along the principal axis is considered positive?

  1. (a) Downwards from the principal axis
  2. (b) Upwards from the principal axis
  3. (c) To the left of the origin (along - x-axis)
  4. (d) To the right of the origin (along + x-axis)
Answer & solution

Answer: (d) To the right of the origin (along + x-axis)

Solution:
In spherical mirrors,direction of incident light is taken as positive
Light travelsfrom left to right
Hence, distances measuredto the right are positive
Answer: To the right of the origin (along + x-axis)
Force and Laws of Motion · Newton's third law and its applications

Q10. Which of the following situations is NOT an example of action and reaction forces?

  1. (a) A swimmer pushing water backwards
  2. (b) A bat hitting a cricket ball
  3. (c) A ball thrown upward comes back down due to the pull of gravity.
  4. (d) A rocket launching upwards
Answer & solution

Answer: (c) A ball thrown upward comes back down due to the pull of gravity.

Option 3 is correct because the ball coming down due to gravity is not an action-reaction pair.
It is a single force acting on the ball (gravity).
Action and reaction forces always act in pairs on two different bodies, equal in magnitude and opposite in direction.
Examples:
1. Swimmer pushes water backwards (action), water pushes swimmer forward (reaction).
2. Bat hits ball (action), ball exerts equal opposite force on bat (reaction).
4. Rocket expels gas downwards (action), gas pushes rocket upwards (reaction).
Thus, option 3 is NOT an example of action and reaction forces.
Final answer: Option 3

Biology (8)

Biotechnology and Applied Biology · Crop improvement and hybridisation

Q11. A farmer wants to grow wheat with better baking quality and resistance to drought. Which two characteristics should be targeted in variety improvement?

  1. (a) Wider adaptability and biotic resistance
  2. (b) Higher yield and wider adaptability
  3. (c) Improved quality and abiotic resistance
  4. (d) Improved quality and biotic resistance
Answer & solution

Answer: (c) Improved quality and abiotic resistance

The farmer needs wheat with better baking quality, which relates to improved quality.
Resistance to drought refers to tolerance against abiotic stress, which is abiotic resistance.
Therefore, the targeted characteristics should be improved quality and abiotic resistance for drought tolerance.
Option 3 correctly matches these requirements.
Final answer: Option 3
Biotechnology and Applied Biology · Agricultural practices (manures, fertilisers, irrigation, weeding)

Q12. How do check-dams help in improving agricultural water availability and soil quality?

  1. (a) They increase groundwater levels and reduce soil erosion.
  2. (b) They directly irrigate fields with river water and increase soil erosion.
  3. (c) They store water only for city use, and reduce soil erosion.
  4. (d) They divert water away from farms and increase soil erosion.
Answer & solution

Answer: (a) They increase groundwater levels and reduce soil erosion.

Check-dams are small barriers built across streams or rivers.
They help increase groundwater levels by slowing water flow and allowing more water to seep into the ground.
This raises the water table which benefits agricultural activities by providing more water.
Check-dams also reduce soil erosion by controlling runoff velocity and preventing soil wash away.
Thus, they improve both water availability for farming and maintain soil quality.
Final answer: Option 1
Biotechnology and Applied Biology · Agricultural practices (manures, fertilisers, irrigation, weeding)

Q13. Plant diseases are caused by pathogens transmitted through:

  1. (a) Sunlight exposure
  2. (b) Crop residues alone
  3. (c) Fertilisers and manure only
  4. (d) Soil, water and air
Answer & solution

Answer: (d) Soil, water and air

Plant diseases are caused by pathogens such as fungi, bacteria, viruses, and nematodes.
These pathogens are transmitted through various environmental agents.
The main carriers include soil, water, and air, which facilitate the spread of pathogens.
Sunlight exposure, crop residues, and fertilisers alone do not transmit pathogens but may influence disease conditions.
Therefore, the correct answer is soil, water and air.
Cell - Structure and Function · Cell membrane and cell wall

Q14. The fluid content inside the plasma membrane is named:

  1. (a) Chromosomes
  2. (b) Genes
  3. (c) Cytoplasm
  4. (d) Chromatin
Answer & solution

Answer: (c) Cytoplasm

The fluid content inside the plasma membrane is called cytoplasm.
It contains the cell organelles and the cytosol (fluid part).
Chromosomes and chromatin are related to the genetic material inside the nucleus.
Genes are segments of DNA, not fluid content.
Therefore, the correct answer is cytoplasm.
Biotechnology and Applied Biology · Agricultural practices (manures, fertilisers, irrigation, weeding)

Q15. What is the primary material used to develop vermicompost?

  1. (a) Chemical fertilisers
  2. (b) Yeast
  3. (c) Earthworms
  4. (d) Bacteria and viruses
Answer & solution

Answer: (c) Earthworms

Option 3 is correct: Earthworms.
Vermicompost is produced by the decomposition of organic waste using earthworms.
Earthworms help break down the waste and convert it into nutrient-rich compost.
This natural process enriches soil and improves plant growth.
Chemical fertilisers, yeast, bacteria, or viruses are not the primary agents in vermicompost production.
Thus, earthworms are the key to vermicompost development.
End of answer.
Ecology and Environment · Pollution - effects on living beings

Q16. Which of the following statements best explains why humans are severely affected by biological magnification?

  1. (a) Humans occupy the top trophic level in many food chains
  2. (b) Humans are best decomposers in food chain
  3. (c) Humans consume less food than other consumers in food chain
  4. (d) Humans can break down toxins
Answer & solution

Answer: (a) Humans occupy the top trophic level in many food chains

Humans are at the top trophic level in many food chains.
Biological magnification causes toxins to concentrate at higher trophic levels.
As top consumers, humans accumulate the highest levels of these toxins.
This leads to severe effects on human health due to toxin accumulation.
Therefore, option 1 is the correct explanation.
Final answer: Option 1
Plant Physiology and Morphology · Transport in plants (xylem, phloem)

Q17. Which of the following tissues ensures that food made in the leaves is delivered to all plant parts?

  1. (a) Mesophyll
  2. (b) Epidermis
  3. (c) Xylem
  4. (d) Phloem
Answer & solution

Answer: (d) Phloem

Option 4 is correct.
Phloem is the tissue responsible for transporting the food prepared in the leaves to other parts of the plant.
It transports organic nutrients, especially sucrose, from leaves to stems, roots, and storage organs.
Xylem, in contrast, transports water and minerals from roots to leaves.
Hence, phloem ensures delivery of food to all plant parts.
Answer closed.
Human Physiology - Respiration, Circulation and Excretion · Excretory system - kidney and nephron

Q18. Which waste based difference between the renal artery and renal vein is directly related to excretory function?

  1. (a) The renal vein has higher pressure
  2. (b) The renal artery has more valves
  3. (c) The renal artery contains more urea
  4. (d) The renal vein contains more oxygen
Answer & solution

Answer: (c) The renal artery contains more urea

Solution:
Therenal arterybrings blood to the kidneys containingmore urea (waste).
Kidneysfilter and remove ureaduring excretion.
Hence, blood in therenal vein has less ureaafter filtration.

Chemistry (10)

Carbon and its Compounds · Soaps and detergents

Q19. In a micelle, which part faces outward toward water?

  1. (a) Hydrocarbon tail
  2. (b) Grease molecule
  3. (c) Non-polar end
  4. (d) Ionic head
Answer & solution

Answer: (d) Ionic head

In a micelle formed by surfactant molecules, the ionic or polar heads face outward.
These ionic heads interact with water, making the micelle soluble in water.
The hydrocarbon tails, which are non-polar, face inward, away from water, to avoid contact with it.
Therefore, the part facing outward in a micelle towards water is the ionic head.
Final answer: Option 4
Environmental Chemistry · Ozone layer and its depletion

Q20. Ozone shields the surface of the Earth from which type of radiation coming from the Sun?

  1. (a) White light
  2. (b) X rays
  3. (c) Infra-red
  4. (d) Ultra violet
Answer & solution

Answer: (d) Ultra violet

Ozone layer is located in the Earth's stratosphere.
It absorbs the majority of the Sun's harmful ultraviolet (UV) radiation.
This protection prevents most UV rays from reaching the Earth's surface.
UV radiation can cause skin cancer and other health issues.
Hence, the ozone layer acts as a shield against ultraviolet radiation from the Sun.
Correct answer is Option 4: Ultra violet.
Matter and its States · States of matter and their properties

Q21. What conclusion can be drawn from the experiment in which potassium permanganate solution remains coloured even after repeated dilution?

  1. (a) Particles of matter are fixed and stationary
  2. (b) Particles of matter occupy no space at all
  3. (c) Particles of matter are visible to naked eye
  4. (d) Particles of matter are extremely small in size
Answer & solution

Answer: (d) Particles of matter are extremely small in size

The potassium permanganate solution remains coloured even after repeated dilution.
This shows that the particles causing colour are very small but still present in the solution.
Hence, the particles of matter must be extremely small in size, allowing the colour to persist despite dilution.
Larger particles would have disappeared or settled out after dilution.
Therefore, the correct conclusion is that particles are extremely small in size.
Final answer: Option 4
Chemistry Miscellaneous · Laboratory apparatus and chemical tests

Q22. When dilute hydrochloric acid reacts with calcium carbonate, the gas evolved is passed through limewater. On passing the gas in excess, the milkiness disappears due to the formation of:

  1. (a) Calcium hydroxide
  2. (b) Calcium oxide
  3. (c) Calcium hydrogen carbonate
  4. (d) Calcium carbonate
Answer & solution

Answer: (c) Calcium hydrogen carbonate

When dilute hydrochloric acid reacts with calcium carbonate, carbon dioxide gas is evolved.
This gas when passed through limewater (calcium hydroxide solution) turns it milky due to formation of calcium carbonate.
When carbon dioxide is passed in excess, the milkiness disappears because soluble calcium hydrogen carbonate is formed.
Hence, the gas reacts with limewater forming calcium carbonate first, then excess CO2 converts it into calcium hydrogen carbonate, removing the milkiness.
Final answer: Option 3
Atoms, Molecules and Mole Concept · Laws of chemical combination

Q23. Which observation supports the law of constant proportions for water?

  1. (a) Hydrogen and oxygen ratio is fixed
  2. (b) Water exists in three states
  3. (c) Water conducts electricity weakly
  4. (d) Water boils at fixed temperature
Answer & solution

Answer: (a) Hydrogen and oxygen ratio is fixed

The law of constant proportions states that a chemical compound always contains the same elements in the same fixed ratio by mass.
For water, this means the ratio of hydrogen to oxygen is always constant.
Option 1 says 'Hydrogen and oxygen ratio is fixed', which directly supports this law.
Other options describe physical properties, not composition ratios.
Hence, option 1 is correct.
Final answer: Option 1
Mixtures, Solutions and Separation · Suspensions and colloids

Q24. Which of the following everyday mixtures is best classified as a suspension?

  1. (a) Chalk powder mixed with water
  2. (b) Sugar completely dissolved in water
  3. (c) Salt solution prepared in water
  4. (d) Copper sulphate dissolved in water
Answer & solution

Answer: (a) Chalk powder mixed with water

Option 1 is correct.
A suspension is a heterogeneous mixture where particles do not dissolve but remain suspended and may settle over time.
Chalk powder in water does not dissolve and settles at the bottom, showing typical suspension behaviour.
Other options involve solutions where substances dissolve completely, forming homogeneous mixtures.
Therefore, chalk powder mixed with water is the best example of a suspension.
Answer ends here.
Atoms, Molecules and Mole Concept · Valency and chemical formulae

Q25. Why are brackets used in the formula Ca(OH)₂?

  1. (a) To show ionic nature
  2. (b) To balance oxygen atoms
  3. (c) To represent molecular bonding
  4. (d) To indicate two hydroxide groups
Answer & solution

Answer: (d) To indicate two hydroxide groups

The brackets in the formula Ca(OH)₂ are used to show that the hydroxide group (OH) is present twice.
It indicates two hydroxide ions are bonded with one calcium ion.
Without brackets, it would be unclear how many OH groups are attached.
Hence, brackets clarify the composition of the compound.
Correct option is 4.
This completes the answer.
Metals and Non-metals · Metallurgy - extraction and refining

Q26. Why are metals such as sodium and calcium extracted by electrolytic reduction instead of heating with carbon?

  1. (a) They have greater affinity for oxygen than carbon
  2. (b) They decompose when heated with carbon
  3. (c) They form unstable oxides at high temperature
  4. (d) They exist only as molten chlorides in nature
Answer & solution

Answer: (a) They have greater affinity for oxygen than carbon

Solution:
Metals likesodium and calcium are highly reactive
They havegreater affinity for oxygen than carbon
So carbon cannot reduce their oxides
Answer: They have greater affinity for oxygen than carbon
Metals and Non-metals · Metallurgy - extraction and refining

Q27. Why are sulphide ores usually converted into oxides before the extraction of metals?

  1. (a) Sulphide ores contain more gangue materials
  2. (b) Metal oxides are easier to reduce than sulphides
  3. (c) Metal sulphides react faster with carbon
  4. (d) Sulphide ores are unstable at room temperature
Answer & solution

Answer: (b) Metal oxides are easier to reduce than sulphides

Solution:
In metallurgy,sulphide ores are first roasted to form oxides
Metal oxides are easier to reduce(by carbon or other reducing agents) than sulphides
Direct reduction of sulphides is difficult and inefficient
Answer: Metal oxides are easier to reduce than sulphides
Matter and its States · Evaporation and its factors

Q28. Why does our palm feel cold when acetone or petrol is poured on it?

  1. (a) The liquid increases moisture on skin surface
  2. (b) The liquid reacts chemically with our skin surface
  3. (c) The liquid blocks heat flow from surroundings
  4. (d) The liquid absorbs heat from the skin to evaporate
Answer & solution

Answer: (d) The liquid absorbs heat from the skin to evaporate

The palm feels cold because acetone or petrol evaporates quickly.
Evaporation requires heat energy, which is taken from the skin’s surface.
This heat absorption reduces skin temperature, causing a cool sensation.
Hence, the liquid absorbs heat from the skin to evaporate, making it feel cold.
Final answer: Option 4

Current Affairs (1)

Science, Technology and Space - Current · Research breakthroughs - current

Q29. What is the primary composition of the stable composite developed by IIT Mandi that prevents 2D semiconductors from degrading?

  1. (a) Boron nitride mixed with epoxy resin
  2. (b) Tungsten disulfide (WS) encapsulated in polydimethylsiloxane (PDMS)
  3. (c) Carbon nanotubes embedded in polymer matrix
  4. (d) Graphene combined with silicone
Answer & solution

Answer: (b) Tungsten disulfide (WS) encapsulated in polydimethylsiloxane (PDMS)

Solution:
Indian Institute of Technology Mandi developed astable composite to protect 2D semiconductors from degradation
The material involvestungsten disulfide (WS₂), a 2D semiconductor
It isencapsulated in polydimethylsiloxane (PDMS)for stability and protection
Answer: Tungsten disulfide (WS₂) encapsulated in polydimethylsiloxane (PDMS)
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