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

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

📚 27 questions🗓️ 20 February 2026⏰ Shift 1
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Subjects: Biology (9) · Physics (9) · Chemistry (9)

Biology (9)

Human Physiology - Respiration, Circulation and Excretion · Respiration and excretion in other organisms

Q1. A plant sheds its leaves and bark to remove stored waste products. How does this strategy differ from the way animals excrete wastes?

  1. (a) Plants use parts that will be shed, while animals have specialized organs for excretion.
  2. (b) Plants use blood circulation for excretion, unlike animals.
  3. (c) Plants use digestive systems to remove waste, unlike animals.
  4. (d) Plants have a single organ system for waste removal, unlike animals.
Answer & solution

Answer: (a) Plants use parts that will be shed, while animals have specialized organs for excretion.

Option 1 is correct.
Plants remove waste by shedding parts like leaves and bark which contain stored waste.
Animals have specialised organs such as kidneys and liver for excretion.
This fundamental difference lies in structural adaptations for waste removal.
Thus, plants lose parts that serve multiple functions while animals use specific organs solely for excretion.
This makes option 1 the accurate description of the difference.
Final answer: Option 1
Biotechnology and Applied Biology · Agricultural practices (manures, fertilisers, irrigation, weeding)

Q2. What is a key difference between chemical fertilisers and manures in terms of nutrient release to plants?

  1. (a) Manures have higher and less variable nutrient concentrations.
  2. (b) Chemical fertilisers enhance biological activity.
  3. (c) Manures release nutrients gradually.
  4. (d) Conventional chemical fertilisers release nutrients gradually.
Answer & solution

Answer: (c) Manures release nutrients gradually.

Chemical fertilisers provide nutrients in readily available forms.
Manures release nutrients gradually as they decompose.
This gradual release from manures ensures a slower, sustained nutrient supply to plants.
Therefore, the key difference is the slower nutrient release by manures compared to chemical fertilisers.
Final answer: Option 3
Cell - Structure and Function · Nucleus and chromosomes

Q3. Where is perinuclear space present?

  1. (a) Inside of the nucleus
  2. (b) Between two layers of the nuclear envelope
  3. (c) Outside the nucleus
  4. (d) Within the nucleolus
Answer & solution

Answer: (b) Between two layers of the nuclear envelope

Perinuclear space is the region between the two membranes of the nuclear envelope.
The nuclear envelope has an inner and an outer membrane, with perinuclear space between them.
It is not inside the nucleus or outside the nucleus, but specifically between the two layers.
Hence, the correct location is between the two layers of the nuclear envelope.
Final answer: Option 2
Cell - Structure and Function · Plant cell and animal cell

Q4. Which of the following is present only in plant cell?

  1. (a) Cell wall
  2. (b) Vacuoles
  3. (c) Nucleus
  4. (d) Endoplasmic reticulum
Answer & solution

Answer: (a) Cell wall

Option 1: Cell wall is found only in plant cells.
Vacuoles, nucleus and endoplasmic reticulum are present in both plant and animal cells.
The cell wall provides structural support and protection to plant cells only.
Hence, cell wall is unique to plant cells among the given options.
Final answer: Option 1
Biotechnology and Applied Biology · Agricultural practices (manures, fertilisers, irrigation, weeding)

Q5. Which two elements are primarily added to soil by green manure?

  1. (a) Potassium and magnesium
  2. (b) Nitrogen and potassium
  3. (c) Nitrogen and phosphorus
  4. (d) Phosphorus and calcium
Answer & solution

Answer: (c) Nitrogen and phosphorus

Green manure is plant material ploughed into the soil to improve fertility.
It adds essential nutrients to the soil.
The two primary elements added by green manure are nitrogen and phosphorus.
Nitrogen improves soil fertility by increasing protein content and microbial activity.
Phosphorus promotes root development and overall plant growth.
Hence, nitrogen and phosphorus are the key nutrients added by green manure.
Final answer: Option 3
Ecology and Environment · Waste management and biodegradable substances

Q6. Why are non-biodegradable substances harmful for the environment?

  1. (a) Causes no pollution in water
  2. (b) Needs heat and temperature for breakdown, releases harmful chemicals
  3. (c) Can be broken down by bacteria
  4. (d) Easily mixes with soil
Answer & solution

Answer: (b) Needs heat and temperature for breakdown, releases harmful chemicals

Option 2 is correct.
Non-biodegradable substances do not decompose easily.
They require heat and temperature for breakdown.
During this process, they release harmful chemicals.
These chemicals pollute the environment.
Hence, they are harmful to the environment.
Final answer: Option 2
Biotechnology and Applied Biology · Animal husbandry, poultry and fisheries

Q7. Why is it important to keep the level of vitamins A and K high in poultry feeds for broilers?

  1. (a) To make broilers resistant to external parasites
  2. (b) To ensure proper nutrition for healthy growth and development
  3. (c) To increase their tolerance to cold weather
  4. (d) To reduce the size of eggs
Answer & solution

Answer: (b) To ensure proper nutrition for healthy growth and development

Option 2 is correct.
Vitamin A is essential for maintaining healthy vision, skin, and immune system in broilers.
Vitamin K plays a crucial role in blood clotting and bone health.
Keeping levels of vitamins A and K high in poultry feeds ensures proper nutrition necessary for healthy growth and development in broilers.
Other options are incorrect as these vitamins do not specifically increase parasite resistance, cold tolerance, or affect egg size.
Hence, the main reason is to support healthy growth and development of broilers.
Final answer: Option 2
Biotechnology and Applied Biology · Animal husbandry, poultry and fisheries

Q8. Why is it important to provide dairy cattle with a sloping floor in their sheds and balanced rations in their diet?

  1. (a) To keep the shed dry and facilitate cleaning, and reduce roughage intake.
  2. (b) To protect from parasites, and increase fibre content.
  3. (c) To keep the shed dry and facilitate cleaning, and to support health and milk production.
  4. (d) To prevent diseases and to support health and milk production.
Answer & solution

Answer: (c) To keep the shed dry and facilitate cleaning, and to support health and milk production.

Solution:
Sloping floor: Ensures proper drainage, keeps shed dry, and makes cleaning easier.
Balanced rations: Provide all necessary nutrients, support health, and improve milk production.
Correct option combines both benefits:dry shed + cleaning + health + milk.
Plant Physiology and Morphology · Photosynthesis - process and factors

Q9. Why is potassium hydroxide used in the bell-jar experiment involving photosynthesis?

  1. (a) To absorb carbon dioxide
  2. (b) To remove water
  3. (c) To supply oxygen
  4. (d) To provide sunlight
Answer & solution

Answer: (a) To absorb carbon dioxide

Potassium hydroxide (KOH) absorbs carbon dioxide (CO2).
In the bell-jar experiment on photosynthesis, CO2 must be removed to prove that plants release oxygen.
KOH helps absorb CO2, ensuring the environment inside the jar is CO2-free.
This shows that oxygen released comes from water splitting, not CO2.
Therefore, KOH is used to absorb CO2 in this experiment.
Final answer: Option 1

Physics (9)

Sound and Waves · Speed of sound in different media

Q10. A sound wave travels from air into water. How does its frequency, speed, and wavelength change as it crosses the boundary?

  1. (a) Its frequency decreases, speed decreases, and wavelength increases
  2. (b) Its frequency remains constant, speed decreases, and wavelength decreases
  3. (c) Its frequency increases, speed remains the same, and wavelength decreases
  4. (d) Its frequency remains constant, speed increases, and wavelength increases
Answer & solution

Answer: (d) Its frequency remains constant, speed increases, and wavelength increases

When a sound wave travels from air to water, its frequency remains constant because frequency depends on the source, not the medium.
The speed of sound increases in water since it is denser and more elastic than air.
Wavelength changes because it is related to speed and frequency by the equation: speed = frequency × wavelength.
Since frequency is constant and speed increases, wavelength must also increase in water.
Final answer: Option 4
Magnetism and Magnetic Effects of Current · Domestic electric circuits, fuse and earthing

Q11. A technician needs to connect a new appliance in a domestic circuit to ensure it receives full voltage and can be operated independently. What should the technician do?

  1. (a) Connect the appliance only to the neutral wire
  2. (b) Connect the appliance in parallel with existing appliances
  3. (c) Connect the appliance in series with existing appliances
  4. (d) Connect the appliance only to the earth wire
Answer & solution

Answer: (b) Connect the appliance in parallel with existing appliances

Correct answer: Option 2
In a domestic circuit, appliances must receive full voltage independently.
Connecting the appliance in parallel ensures it gets full voltage.
Series connection divides voltage among appliances, so not suitable.
Connection to neutral or earth alone won't power the appliance.
Therefore, connect the appliance in parallel with existing ones.
This is standard practice for household wiring.
This ensures safety and proper operation.
Answer complete.
Human Eye and the Colourful World · Defects of vision and their correction

Q12. A young child is diagnosed with both myopia and hypermetropia in different eyes. What is the most appropriate corrective approach?

  1. (a) Providing glasses with different lenses for each eye (concave for one, convex for the other)
  2. (b) Using bifocal lenses in both eyes
  3. (c) Using cylindrical lenses in both eyes
  4. (d) Providing identical convex lenses for both eyes
Answer & solution

Answer: (a) Providing glasses with different lenses for each eye (concave for one, convex for the other)

A child diagnosed with myopia (nearsightedness) in one eye and hypermetropia (farsightedness) in the other requires different lens types for each eye.
Myopia is corrected by concave lenses that diverge light rays.
Hypermetropia is corrected by convex lenses that converge light rays.
Therefore, the child must be given glasses with different lenses for each eye: concave for myopic eye, convex for hypermetropic eye.
This corrects vision in both eyes appropriately.
Final answer: Option 1
Light - Reflection and Mirrors · Spherical mirror terminology

Q13. If a point is located below the principal axis of a spherical mirror, what sign is assigned to its perpendicular distance according to the sign convention for spherical mirrors?

  1. (a) Depends on mirror type
  2. (b) Negative
  3. (c) Positive
  4. (d) Zero
Answer & solution

Answer: (b) Negative

According to the sign convention for spherical mirrors, distances measured below the principal axis are assigned a negative sign.
This applies for perpendicular distances from the principal axis.
Therefore, if a point lies below the principal axis, its perpendicular distance is negative.
Final answer: Option 2
Force and Laws of Motion · Centripetal and centrifugal force

Q14. Suppose a student wants to design an amusement park ride that moves people in a circle at uniform speed. Which concept should the student apply to ensure riders stay safely in their seats during the circular motion?

  1. (a) Increasing speed randomly will keep them safe
  2. (b) A constant outward force is needed to keep riders pressed against their seats
  3. (c) A constant inward (centripetal) force is needed on the riders to keep them in uniform circular motion
  4. (d) Gravity alone is sufficient to keep the riders in place
Answer & solution

Answer: (c) A constant inward (centripetal) force is needed on the riders to keep them in uniform circular motion

Correct option is 3
To keep riders safely in their seats during circular motion, a constant inward force (centripetal force) is required.
This inward force acts towards the centre of the circle and maintains uniform circular motion.
It prevents riders from flying outward due to inertia.
Therefore, the ride must provide centripetal force to keep riders moving in a circle safely.
Options 1, 2 and 4 are incorrect because:
1 is unsafe as randomly increasing speed does not provide controlled force.
2 is wrong because the force is inward, not outward.
4 is incorrect as gravity alone cannot provide the necessary centripetal force.
This is a fundamental principle in circular motion in physics.
Answer is Option 3.
Work, Energy and Power · Work and its sign

Q15. What happens to the work done if the displacement becomes zero despite a force being applied?

  1. (a) The work done remains constant.
  2. (b) The work done decreases.
  3. (c) The work done increases.
  4. (d) The work done is zero.
Answer & solution

Answer: (d) The work done is zero.

Work done is calculated by the formula: Work = Force × Displacement × cos(θ).
If displacement is zero, then Work = Force × 0 × cos(θ) = 0.
Thus, no matter how much force is applied, if there is no displacement, the work done is zero.
Therefore, the correct answer is option 4.
Light - Reflection and Mirrors · Concave mirror - image formation and uses

Q16. When an object is placed at the center of curvature (C) of a concave mirror, what is the nature of the image formed?

  1. (a) Real and inverted
  2. (b) Highly diminished, point-sized
  3. (c) Virtual and erect
  4. (d) Enlarged and inverted
Answer & solution

Answer: (a) Real and inverted

When an object is placed at the centre of curvature (C) of a concave mirror,
the image forms at the centre of curvature itself.
The image is real because the light rays actually converge at this point.
It is inverted as the rays cross each other.
The size of the image is equal to the size of the object.
Hence, the correct nature of the image is: real and inverted.
Final answer: Option 1
Magnetism and Magnetic Effects of Current · Force on a current-carrying conductor and Fleming's left-hand rule

Q17. Which rule helps to determine the direction of force acting on a current-carrying conductor in a magnetic field?

  1. (a) Fleming's left-hand rule
  2. (b) Faraday's law
  3. (c) Ampere's rule
  4. (d) Right-hand rule
Answer & solution

Answer: (a) Fleming's left-hand rule

The question asks which rule determines the direction of force on a current-carrying conductor in a magnetic field.
Fleming's left-hand rule is used to find the direction of force on the conductor.
In this rule, the thumb indicates the direction of force, the forefinger the magnetic field, and the middle finger the current.
Other options like Faraday's law relate to electromagnetic induction, Ampere's rule is for magnetic field direction, and the right-hand rule is commonly used for different magnetic phenomena.
Hence, Fleming's left-hand rule is the correct choice.
Final answer: Option 1
Electricity · Electric circuits and circuit symbols

Q18. Why does a torch bulb glow only when the switch is turned on?

  1. (a) Because the bulb is in series with the cell
  2. (b) Because the bulb is functional
  3. (c) Because the switch completes the circuit, allowing current to flow
  4. (d) Because the battery is charged
Answer & solution

Answer: (c) Because the switch completes the circuit, allowing current to flow

The bulb in a torch glows only when the switch is turned on because the switch completes the electrical circuit.
When the circuit is complete, current can flow from the battery through the bulb.
If the switch is off, the circuit is open and current cannot flow, so the bulb does not glow.
Hence, the switch controls whether the current flows or not by completing or breaking the circuit.
Final answer: Option 3

Chemistry (9)

Metals and Non-metals · Chemical properties of metals

Q19. Magnesium ribbon burns with:

  1. (a) A bright white flame
  2. (b) A yellow luminous flame
  3. (c) A blue non-luminous flame
  4. (d) No visible flame
Answer & solution

Answer: (a) A bright white flame

Magnesium ribbon burns in air with a bright white flame.
This is due to the high temperature of burning magnesium and the formation of magnesium oxide.
Hence, the correct observation is a bright white flame.
Final answer: Option 1
Carbon and its Compounds · Soaps and detergents

Q20. Which change will promote micelle formation in a detergent solution?

  1. (a) Adding more water to dilute the solution
  2. (b) Increasing detergent concentration above Critical Micelle Concentration(CMC)
  3. (c) Lowering the temperature below Kraft point
  4. (d) Decreasing detergent concentration below Critical Micelle Concentration(CMC)
Answer & solution

Answer: (b) Increasing detergent concentration above Critical Micelle Concentration(CMC)

Explanation:
Micelles form only when detergent concentration exceeds the Critical Micelle Concentration (CMC).
Below CMC, detergent molecules remainseparate in solution.
When concentration becomesgreater than CMC, moleculesaggregate to form micelles.
Therefore,increasing detergent concentration above CMC promotes micelle formation.
Metals and Non-metals · Reactivity series

Q21. Which metal listed below shows the strongest reaction when added to dilute hydrochloric acid?

  1. (a) Iron
  2. (b) Copper
  3. (c) Zinc
  4. (d) Magnesium
Answer & solution

Answer: (d) Magnesium

Option 4 is correct: Magnesium shows the strongest reaction with dilute hydrochloric acid.
Magnesium reacts vigorously with dilute HCl producing hydrogen gas rapidly.
The reaction strength order with dilute HCl is generally: Magnesium > Zinc > Iron > Copper.
Copper does not react with dilute hydrochloric acid as it is less reactive than hydrogen.
Therefore, Magnesium is the most reactive metal among the options given when added to dilute hydrochloric acid.
This is a common question tested in competitive exams to check reactivity series knowledge.
Hence, the strongest reaction is observed with Magnesium.
Final answer: Option 4
Atoms, Molecules and Mole Concept · Atomic mass and molecular mass

Q22. Which of the following compounds has a formula unit mass of 100 u?

  1. (a) MgO
  2. (b) Na2CO3
  3. (c) CaCl2
  4. (d) CaCO3
Answer & solution

Answer: (d) CaCO3

We calculate formula unit mass by adding atomic masses of each atom in the formula.
Option 1: MgO = Mg (24) + O (16) = 40 u.
Option 2: Na2CO3 = 2×Na (23) + C (12) + 3×O (16) = 46 + 12 + 48 = 106 u.
Option 3: CaCl2 = Ca (40) + 2×Cl (35.5) = 40 + 71 = 111 u.
Option 4: CaCO3 = Ca (40) + C (12) + 3×O (16) = 40 + 12 + 48 = 100 u.
Therefore, CaCO3 has a formula unit mass of 100 u.
Final answer: Option 4
Carbon and its Compounds · Ethanol and ethanoic acid

Q23. Which of the following does NOT describe a property of ethanol (C₂H₅OH)?

  1. (a) It is soluble in water in all proportions.
  2. (b) It is a clear, colourless liquid with a pleasant smell.
  3. (c) It turns blue litmus paper red.
  4. (d) It reacts with sodium to release hydrogen gas.
Answer & solution

Answer: (c) It turns blue litmus paper red.

Ethanol (C₂H₅OH) is neutral or very weakly acidic, so it does NOT turn blue litmus paper red.
It is soluble in water in all proportions due to hydrogen bonding with water molecules.
Ethanol is a clear, colourless liquid with a pleasant smell.
It reacts with sodium metal releasing hydrogen gas as per the reaction: 2 C₂H₅OH + 2 Na → 2 C₂H₅ONa + H₂.
Hence, the correct choice is the statement that it turns blue litmus red, which is false for ethanol.
Final answer: Option 3
Carbon and its Compounds · Chemical properties of carbon compounds (combustion, oxidation, addition, substitution)

Q24. Which of the following statements is TRUE for all saturated hydrocarbons?

  1. (a) They contain at least one double bond.
  2. (b) They show substitution reactions rather than addition reactions.
  3. (c) They readily undergo addition reactions.
  4. (d) They are generally very reactive due to triple bonds.
Answer & solution

Answer: (b) They show substitution reactions rather than addition reactions.

Correct option: 2
Saturated hydrocarbons are alkanes with single bonds only.
They do not have double or triple bonds, so options 1 and 4 are incorrect.
Saturated hydrocarbons undergo substitution reactions rather than addition reactions because addition requires unsaturation (double/triple bonds).
Therefore, they show substitution reactions instead of addition.
Hence, option 2 is true for all saturated hydrocarbons.
This matches the chemical behaviour of saturated hydrocarbons exactly.
Mixtures, Solutions and Separation · Solutions, solubility and concentration

Q25. Which property explains why the path of light is not visible when a beam passes through a true solution?

  1. (a) Particles can be removed by filtration
  2. (b) Particles are smaller than one nanometre
  3. (c) Particles settle down on standing still
  4. (d) Particles are heavier than solvent molecules
Answer & solution

Answer: (b) Particles are smaller than one nanometre

The path of light is not visible in a true solution because the particles in it are extremely small.
In a true solution, particles are smaller than one nanometre in size.
Such tiny particles do not scatter light, so the beam of light remains invisible when passing through the solution.
The Tyndall effect, which makes light visible, occurs only if the particles are larger, like in colloids.
Hence, the reason is the very small size of particles in a true solution.
Final answer: Option 2
Mixtures, Solutions and Separation · Homogeneous and heterogeneous mixtures

Q26. Which statement correctly describes a heterogeneous mixture?

  1. (a) Its composition is not uniform throughout the mixture
  2. (b) Its components cannot be separated by physical methods
  3. (c) Its composition remains fixed and constant always
  4. (d) Its particles are uniformly distributed at particle level
Answer & solution

Answer: (a) Its composition is not uniform throughout the mixture

Option 1 is correct.
A heterogeneous mixture has a non-uniform composition.
Different components can be seen distinctly.
Components can be physically separated.
Other options describe properties of homogeneous mixtures or pure substances.
Thus, option 1 correctly describes a heterogeneous mixture.
Final answer: Option 1
Matter and its States · States of matter and their properties

Q27. Why are solids described as rigid in nature?

  1. (a) Their particles possess very low mass and volume
  2. (b) Their particles are closely packed with strong attraction
  3. (c) Their particles slide easily under applied external force
  4. (d) Their particles move freely with weak mutual attraction
Answer & solution

Answer: (b) Their particles are closely packed with strong attraction

Solids are called rigid because their particles are very closely packed.
This close packing results in strong attractive forces between particles.
Strong attraction keeps the particles fixed in position, limiting movement.
Due to this, solids maintain a definite shape and resist deformation.
Hence, solids appear rigid under external forces.
Final answer: Option 2
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