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RRB JE CBT-1 2025-26 20 February 2026 Shift 3 GK Questions – with answers & solutions

All 27 GK / GS questions asked in RRB JE CBT-1 2025-26 on 20 February 2026 Shift 3, with correct answers and short solutions, subject-wise: Chemistry, Physics, Biology.

📚 27 questions🗓️ 20 February 2026⏰ Shift 3
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Subjects: Chemistry (9) · Physics (9) · Biology (9)

Chemistry (9)

Atoms, Molecules and Mole Concept · Valency and chemical formulae

Q1. Refer to the two statements given below and choose the CORRECT option.Statement A: While writing the chemical formula of a compound, the total positive and negative charges must balance each other.Statement B: Balancing valencies ensures that the compound formed is electrically neutral.

  1. (a) Statement A is correct but B is incorrect.
  2. (b) Statement A is incorrect but B is correct.
  3. (c) Both statements A and B are correct.
  4. (d) Both statements A and B are incorrect.
Answer & solution

Answer: (c) Both statements A and B are correct.

Both statements A and B talk about electrical charge balance in chemical compounds.
Statement A is correct: Chemical formula writing requires total positive and negative charges to balance.
Statement B is also correct: Balancing valencies ensures the compound formed is electrically neutral.
Hence, both statements are true and related concepts in chemistry.
Final answer: Option 3
Carbon and its Compounds · Soaps and detergents

Q2. A micelle has its hydrophobic ends directed:

  1. (a) Randomly in all possible directions
  2. (b) Towards water molecules directly
  3. (c) Outside forming hydrogen bonds
  4. (d) Towards the center away from water
Answer & solution

Answer: (d) Towards the center away from water

A micelle is an aggregate of surfactant molecules in a liquid colloid.
The hydrophobic (water-fearing) ends aggregate away from water.
These hydrophobic ends point towards the centre of the micelle.
The hydrophilic (water-loving) ends face outward, interacting with water molecules.
Thus, hydrophobic ends are towards the centre, away from water.
Correct option is 4.
Final answer: Option 4
Chemical Reactions and Equations · Double displacement and precipitation reactions

Q3. A student adds lead (II) nitrate (Pb(NO₃)₂) to an unknown solution. A yellow precipitate forms. What could the unknown solution be?

  1. (a) Copper sulphate (CuSO4)
  2. (b) Sodium chloride (NaCl)
  3. (c) Potassium iodide (KI)
  4. (d) Barium sulphate (BaSO4)
Answer & solution

Answer: (c) Potassium iodide (KI)

The yellow precipitate formed when lead (II) nitrate is added indicates the formation of lead iodide (PbI2).
Lead iodide is a bright yellow solid formed by the reaction of Pb(NO3)2 with potassium iodide (KI).
Thus, the unknown solution must contain iodide ions, i.e., it is potassium iodide (KI).
Final answer: Option 3
Acids, Bases and Salts · Common salts - preparation and uses (baking soda, washing soda, bleaching powder, plaster of Paris)

Q4. Identify the CORRECT statement about the chlor-alkali process:

  1. (a) Sodium hydroxide is generated near the anode during electrolysis.
  2. (b) Hydrogen gas is formed at the cathode and chlorine gas at the anode.
  3. (c) It is used for the preparation of Na2CO3 solution by electrolysis of brine.
  4. (d) NaOH is formed at the anode and chlorine gas at the cathode.
Answer & solution

Answer: (b) Hydrogen gas is formed at the cathode and chlorine gas at the anode.

In the chlor-alkali process, brine (NaCl solution) is electrolysed.
At the cathode, hydrogen gas is produced by reduction of H+ ions.
At the anode, chlorine gas is produced by oxidation of chloride ions.
Sodium hydroxide (NaOH) is formed in the solution but not near the anode.
Hence, hydrogen gas forms at cathode and chlorine gas at anode is correct.
Final answer: Option 2
Acids, Bases and Salts · Common salts - preparation and uses (baking soda, washing soda, bleaching powder, plaster of Paris)

Q5. Washing soda is commonly used to:

  1. (a) Remove grease and soften water
  2. (b) Neutralise acids in human blood
  3. (c) Preserve meat for long periods
  4. (d) Increase acidity in baked foods
Answer & solution

Answer: (a) Remove grease and soften water

Washing soda is sodium carbonate decahydrate (Na2CO3·10H2O).
It is commonly used in households to remove grease stains from clothes and other surfaces.
It also softens hard water by removing calcium and magnesium ions.
Hence, the main use of washing soda is to remove grease and soften water.
Option 1 is correct.
Final answer: Option 1
Metals and Non-metals · Metallurgy - extraction and refining

Q6. What happens to insoluble impurities during electrolytic refining?

  1. (a) They dissolve completely
  2. (b) They settle as anode mud
  3. (c) They deposit on cathode
  4. (d) They evaporate
Answer & solution

Answer: (b) They settle as anode mud

In electrolytic refining, the impure metal acts as the anode.
When current passes, the pure metal dissolves and deposits at the cathode.
Insoluble impurities do not dissolve; instead, they settle down at the bottom.
This residue collected at the bottom of the anode is called anode mud or anode slime.
Hence, insoluble impurities settle as anode mud during the process.
Periodic Classification of Elements · Element families (alkali, alkaline earth, halogens, noble gases)

Q7. Which element exists as a monoatomic molecule?

  1. (a) Argon
  2. (b) Chlorine
  3. (c) Nitrogen
  4. (d) Oxygen
Answer & solution

Answer: (a) Argon

Correct option: 1
Argon is a noble gas and exists as a monoatomic molecule.
Other elements like chlorine, nitrogen, and oxygen exist as diatomic molecules (Cl2, N2, O2 respectively).
Monoatomic molecules mean single atoms exist independently, which is characteristic of noble gases.
Hence, argon exists as a monoatomic molecule.
Acids, Bases and Salts · Indicators (natural, synthetic, olfactory)

Q8. Which pair of olfactory indicators loses its smell in a basic solution?

  1. (a) Onion and blue litmus
  2. (b) Vanilla essence and clove oil
  3. (c) Phenolphthalein and onion
  4. (d) Turmeric and onion
Answer & solution

Answer: (b) Vanilla essence and clove oil

Option 2 is correct: Vanilla essence and clove oil lose their smell in a basic solution.
These compounds are sensitive to pH changes and typically lose their characteristic aroma in alkaline conditions.
Other options include substances that either are not primarily olfactory indicators or do not lose smell in base.
Hence, the correct answer is Vanilla essence and clove oil.
Everyday and Industrial Chemistry · Fuels and calorific value (LPG, CNG, coal, petroleum)

Q9. Why is alcohol considered a cleaner fuel than petrol?

  1. (a) It burns without oxygen
  2. (b) It gives higher energy
  3. (c) It burns at low temperature
  4. (d) It produces less smoke
Answer & solution

Answer: (d) It produces less smoke

Alcohol is considered a cleaner fuel than petrol because it produces less smoke on burning.
Less smoke means fewer pollutants and particulates are released into the air.
This makes alcohol a cleaner option for the environment compared to petrol.
Hence, option 4 is correct.
Final answer: Option 4

Physics (9)

Light - Refraction and Lenses · Concave lens - image formation and uses

Q10. A designer wants to create a device that spreads light from a small bulb to illuminate a wide area uniformly. Which lens should be used and why?

  1. (a) A concave lens, because it diverges light rays outward
  2. (b) A convex lens, because it converges light rays
  3. (c) A plane glass, because it transmits light without bending
  4. (d) A prism, because it bends light at an angle
Answer & solution

Answer: (a) A concave lens, because it diverges light rays outward

Correct option: 1
A concave lens diverges light rays outward.
This divergence helps spread light from a small bulb over a wide area.
Hence, concave lens is suitable to illuminate a wide area uniformly.
Convex lenses converge rays, focusing light on a small spot, which is not ideal here.
Plane glass simply passes light without spreading it.
Prisms bend light but do not uniformly spread it.
Therefore, the best choice is a concave lens for spreading light uniformly.
Final answer: Option 1
Force and Laws of Motion · Newton's first law and inertia

Q11. A passenger in a moving car feels a jerk backward when the car suddenly starts. How does the first law of motion explain this experience?

  1. (a) The passenger tends to remain at rest while the car moves forward, showing inertia.
  2. (b) The passenger is pushed backward by the air inside the car.
  3. (c) The seat pushes the passenger forward, causing the sensation.
  4. (d) Friction from the seat creates the backward jerk.
Answer & solution

Answer: (a) The passenger tends to remain at rest while the car moves forward, showing inertia.

According to Newton's first law, an object at rest tends to stay at rest unless acted upon by an external force.
When the car suddenly starts moving forward, the passenger's body tends to remain at rest due to inertia.
This causes the passenger to feel a backward jerk as their body resists the forward motion of the car.
Hence, the backward jerk is explained by inertia keeping the passenger at rest while the car moves forward.
Final answer: Option 1
Electricity · Numericals on electricity

Q12. A wire of a given material has length l and cross-sectional area A , and its resistance is 9 Ω. Another wire of the same material has length l/3 and cross-sectional area 3A. What will be the resistance of the second wire?

  1. (a) 6 Ω
  2. (b) 0.5 Ω
  3. (c) 1 Ω
  4. (d) 2 Ω
Answer & solution

Answer: (c) 1 Ω

Solution:
ResistanceR=ρ(L)/(A)
First wire:R_(1)=9Ω=ρ(l)/(A)
Second wire:R_(2)=ρ(l/3)/(3A)=ρ(l)/(9A)=(R_(1))/(9)=1Ω
Electricity · Numericals on electricity

Q13. An electric refrigerator has a power rating of 500 W and is used for 6 hours each day. If the cost of electrical energy is ₹4.00 per kilowatt-hour, what will be the total cost of operating the refrigerator for 30 days?

  1. (a) ₹180
  2. (b) ₹360
  3. (c) ₹300
  4. (d) ₹240
Answer & solution

Answer: (b) ₹360

The power rating of the refrigerator is 500 W, i.e., 0.5 kW.
Daily energy consumption = power x time = 0.5 kW x 6 hours = 3 kWh per day.
For 30 days, energy consumed = 3 kWh/day x 30 days = 90 kWh.
Cost of electrical energy = ₹4.00 per kWh.
Total cost = 90 kWh x ₹4 = ₹360.
Therefore, the total cost of operating the refrigerator for 30 days is ₹360.
Final answer: Option 2
Human Eye and the Colourful World · Atmospheric refraction (twinkling of stars, advance sunrise)

Q14. If atmospheric refraction did not occur, which change would be most noticeable during the observation of stars from Earth?

  1. (a) Stars would change color rapidly.
  2. (b) Stars would disappear from the night sky.
  3. (c) Planets would twinkle like stars.
  4. (d) Stars would not twinkle; their light would remain steady.
Answer & solution

Answer: (d) Stars would not twinkle; their light would remain steady.

Atmospheric refraction causes the bending of starlight as it passes through Earth's atmosphere.
This bending leads to the apparent twinkling (scintillation) of stars.
Without atmospheric refraction, starlight would not bend or be distorted.
Therefore, stars would not appear to twinkle but shine with a steady light.
Planets do not twinkle much because they have a larger apparent size, averaging out atmospheric effects.
Hence, the most noticeable change would be the disappearance of the twinkling effect in stars.
Correct answer is option 4.
Answer complete.
Work, Energy and Power · Potential energy

Q15. What happens to the potential energy of an object if its mass is halved while its height above the ground remains constant?

  1. (a) The potential energy becomes zero
  2. (b) The potential energy is halved
  3. (c) The potential energy remains unchanged
  4. (d) The potential energy is doubled
Answer & solution

Answer: (b) The potential energy is halved

Potential energy (PE) is given by the formula: PE = mgh, where:
m = mass of the object,
g = acceleration due to gravity,
h = height above the ground.
If the mass is halved, m becomes m/2, while g and h remain constant.
So, new potential energy = (m/2) × g × h = (1/2) × original potential energy.
Therefore, the potential energy is halved when the mass is halved, keeping height constant.
Final answer: Option 2
Electricity · Potential difference and EMF

Q16. What is the reason why electrons move in a conducting wire when connected to a battery, but not when the wire is left untouched?

  1. (a) A battery creates a potential difference that sets electrons in motion
  2. (b) Gravity acts on electrons in the wire
  3. (c) Wire is made of copper
  4. (d) Electrons have intrinsic energy for movement
Answer & solution

Answer: (a) A battery creates a potential difference that sets electrons in motion

When a conducting wire is connected to a battery,
the battery creates a potential difference (voltage) across the wire.
This potential difference causes electrons to move, generating an electric current.
If the wire is left untouched (not connected to a battery),
there is no potential difference to push the electrons, so they do not move.
Gravity does not have a significant effect on electrons in the wire,
and simply being made of copper does not cause electron movement.
Electrons do not move spontaneously without an external force like a battery.
Final answer: Option 1
Magnetism and Magnetic Effects of Current · Solenoid and electromagnet

Q17. Which material can be magnetised using the strong magnetic field inside a solenoid?

  1. (a) Aluminum
  2. (b) Plastic
  3. (c) Copper
  4. (d) Soft iron
Answer & solution

Answer: (d) Soft iron

Soft iron can be magnetised by placing it inside a strong magnetic field such as inside a solenoid.
This is because soft iron is a ferromagnetic material that easily gains magnetic properties when subjected to an external magnetic field.
Materials like aluminum, plastic, and copper are not easily magnetised as they are paramagnetic or diamagnetic and do not retain magnetism.
Therefore, the correct choice is soft iron.
Final answer: Option 4
Work, Energy and Power · Conservation and transformation of energy

Q18. Which statement accurately describes how energy transforms during the free fall of an object under gravity?

  1. (a) Potential energy and kinetic energy both decrease.
  2. (b) Potential energy is converted into heat energy during the fall.
  3. (c) Both potential and kinetic energies remain constant.
  4. (d) Potential energy decreases while kinetic energy increases, maintaining constant total mechanical energy.
Answer & solution

Answer: (d) Potential energy decreases while kinetic energy increases, maintaining constant total mechanical energy.

Option 4 is correct.
During free fall under gravity, an object's potential energy decreases as it moves downwards.
This lost potential energy converts into kinetic energy, increasing the object's speed.
The total mechanical energy (potential + kinetic) remains constant if we ignore air resistance.
Hence, the energy transforms from potential to kinetic, conserving total mechanical energy throughout the fall.
This is a direct consequence of the law of conservation of energy in a gravitational field.
Final answer: Option 4

Biology (9)

Biotechnology and Applied Biology · Apiculture and sericulture

Q19. A farmer wants to improve both the quantity and taste of honey produced on his bee farm. Which of the following strategies should he adopt?

  1. (a) Reduce the number of beehives and increase the number of bees.
  2. (b) Increase the variety and quantity of flowering plants near the beehives.
  3. (c) Use only local bee varieties for honey production.
  4. (d) Move the apiary to an area with fewer flowers.
Answer & solution

Answer: (b) Increase the variety and quantity of flowering plants near the beehives.

Correct option: 2
To improve quantity and taste of honey, increasing variety and quantity of flowering plants helps bees get more nectar sources.
More nectar variety improves honey flavour and more flowers increase honey production.
Reducing hives or restricting to local bees doesn't ensure better taste or quantity.
Moving apiary to fewer flowers reduces nectar availability, lowering production.
Hence, option 2 is best.
Final answer: Option 2
Human Physiology - Respiration, Circulation and Excretion · Respiration and excretion in other organisms

Q20. A gardener notices fallen leaves under a tree. Which strategy of plant excretion does this illustrate, and what type of waste handling is involved?

  1. (a) Converting waste into fruits.
  2. (b) Excreting waste through roots only.
  3. (c) Storing waste in leaves that fall off.
  4. (d) Releasing waste as oxygen only.
Answer & solution

Answer: (c) Storing waste in leaves that fall off.

Correct option is 3.
Plants produce waste materials like phenols and tannins.
These wastes are stored in leaves or other parts.
When leaves fall off, they remove stored waste from the plant body.
This natural disposal method is a plant excretion strategy.
Hence, fallen leaves under the tree show storage of waste in leaves that fall off.
Final answer: Option 3
Ecology and Environment · Pollution - effects on living beings

Q21. A town replaces all plastic bags with cloth bags. Which chain reaction is expected in the ecosystem?

  1. (a) Reduced pollution and decreased biological magnification
  2. (b) Cloth bags cause soil toxicity
  3. (c) Plastic still enters the food chain
  4. (d) More plastic accumulates in water bodies
Answer & solution

Answer: (a) Reduced pollution and decreased biological magnification

Replacing plastic bags with cloth bags reduces plastic pollution.
Less plastic pollution leads to decreased biological magnification.
Biological magnification happens when toxins accumulate in organisms higher up the food chain.
Therefore, using cloth bags benefits the ecosystem by reducing pollution and biological magnification.
Final answer: Option 1
Human Physiology - Respiration, Circulation and Excretion · Heart - structure and functioning

Q22. If the bicuspid (mitral) valve fails to close properly, which immediate effect is most likely during ventricular contraction?

  1. (a) Backflow of blood from the right ventricle to the right atrium
  2. (b) Mixing of oxygenated and deoxygenated blood in the ventricles
  3. (c) Backflow of blood from the left ventricle to the left atrium
  4. (d) Reduced flow of blood to the lungs
Answer & solution

Answer: (c) Backflow of blood from the left ventricle to the left atrium

The bicuspid (mitral) valve is located between the left atrium and left ventricle.
Its function is to prevent blood from flowing backward into the atrium when the ventricle contracts.
If it fails to close properly, blood will flow back from the left ventricle to the left atrium during ventricular contraction.
This condition is called mitral regurgitation and causes inefficiency in the heart's pumping action.
Final answer: Option 3
Ecology and Environment · Food chains and food webs

Q23. In a pond ecosystem, removal of phytoplankton would most directly affect ____________.

  1. (a) Abiotic components
  2. (b) Secondary consumers like fish-eating birds
  3. (c) Decomposers only
  4. (d) Primary consumers like zooplankton
Answer & solution

Answer: (d) Primary consumers like zooplankton

The removal of phytoplankton removes the primary producers in the pond ecosystem.
Phytoplankton are the main food source for primary consumers such as zooplankton.
Without phytoplankton, primary consumers like zooplankton will be directly affected as their food source disappears.
Abiotic components, secondary consumers, and decomposers are indirectly affected, but the most direct impact is on primary consumers.
Therefore, the correct answer is primary consumers like zooplankton.
Correct option is 4.
Final answer: Option 4
Biotechnology and Applied Biology · Food production and storage

Q24. Which of the following is a biotic factor causing storage losses in grains?

  1. (a) Insects
  2. (b) Temperature
  3. (c) Sunlight
  4. (d) Moisture
Answer & solution

Answer: (a) Insects

Biotic factors are living organisms that affect other living things.
Insects are living organisms that can infest grain storage and cause losses.
Temperature, sunlight, and moisture are abiotic (non-living) factors affecting grains.
Therefore, insects are the biotic factor causing storage losses in grains.
Final answer: Option 1
Tissues · Connective tissue (blood, bone, cartilage, ligament, tendon)

Q25. Which of the following types of connective tissue is present in the larynx of a human body?

  1. (a) Areolar
  2. (b) Ligament
  3. (c) Adipose
  4. (d) Cartilage
Answer & solution

Answer: (d) Cartilage

The larynx in the human body is primarily composed of cartilage.
Cartilage is a type of connective tissue that provides structure and support.
Among the options, cartilage correctly matches the tissue type of the human larynx.
Hence, the type of connective tissue present in the larynx is cartilage.
Final answer: Option 4
Biotechnology and Applied Biology · Agricultural practices (manures, fertilisers, irrigation, weeding)

Q26. Why are crops with different nutrient requirements chosen for inter-cropping?

  1. (a) To prevent all pests and diseases completely
  2. (b) To ensure maximum utilisation of nutrients supplied to the field
  3. (c) To increase the duration of crop growth
  4. (d) To allow for crop rotation in succession
Answer & solution

Answer: (b) To ensure maximum utilisation of nutrients supplied to the field

Inter-cropping involves growing different crops together on the same field.
Choosing crops with different nutrient needs ensures that the soil nutrients are utilised efficiently.
This prevents nutrient competition and maximises overall nutrient uptake from the soil.
Therefore, nutrient utilisation is improved, leading to better crop yield and soil health.
Hence, the correct reason is to ensure maximum utilisation of nutrients supplied to the field.
Final answer: Option 2
Nutrition and Digestion · Nutrition in animals (amoeba, ruminants)

Q27. Why is intracellular digestion suitable for unicellular organisms?

  1. (a) They lack specialized digestive organs.
  2. (b) They have large body cavities.
  3. (c) They lack digestive enzymes.
  4. (d) They depend on external digestion.
Answer & solution

Answer: (a) They lack specialized digestive organs.

Unicellular organisms do not have specialised digestive organs.
Therefore, digestion occurs inside the cell itself, known as intracellular digestion.
It allows them to break down food within their own cellular structures efficiently.
Hence, intracellular digestion is suitable because of the absence of specialised digestive systems.
Final answer: Option 1
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