RRB JE General Science Questions with Detailed Solutions

Get RRB JE General Science Questions to prepare for your upcoming exam. Solve the most expected questions and detailed solutions that can be asked in the exam.

Important RRB JE General Science Questions

Q1.

Nita is pregnant, but loves to eat junk food. Her doctor advised her to eat salads and fruits. The reason for this advice is:

  • A.

    junk food is tasty, but leads to obesity

  • B.

    the nutrients in the mother's blood nourishes the growing baby

    ✓ Correct
  • C.

    junk food is costly in comparison to salad and fruits

  • D.

    the mother's blood has no role in the growth of a baby

Answer & Solution

Correct option is B

The correct answer is (B) the nutrients in the mother's blood nourishes the growing baby.

Explanation:

  • During pregnancy, a baby gets all its nutrients from the mother’s blood through the placenta.
  • Eating healthy foods like salads and fruits ensures that the baby receives essential vitamins, minerals, and fiber for proper development.
  • Junk food lacks essential nutrients and can lead to poor fetal growth and complications.

Information Booster:

  • Folic acid, iron, calcium, and protein are crucial nutrients for a healthy pregnancy.
  • Excessive junk food can increase the risk of gestational diabetes, high blood pressure, and obesity.
  • The placenta acts as a bridge between the mother and the baby, supplying oxygen and nutrients.

Additional Information:

  • Junk food is tasty but leads to obesity (A): True, but not the main reason for avoiding it during pregnancy.
  • Junk food is costly in comparison to salad and fruits (C): Cost is irrelevant to health benefits.
  • The mother’s blood has no role in the growth of a baby (D): Incorrect, as the mother’s blood is essential for the baby’s nutrition and growth.
Q2.

Which of the following plants propagates through runners?

  • A.

    Jasmine

  • B.

    Potato

  • C.

    Strawberry

    ✓ Correct
  • D.

    Rose

Answer & Solution

Correct option is C

The correct answer is (C) Strawberry.

Explanation:

  • Strawberry propagates through runners, which are horizontal stems that grow along the ground.
  • These runners develop adventitious roots, forming new plants, allowing vegetative reproduction.

Information Booster:

  • Runners (Stolons): Specialized horizontal stems that help plants spread rapidly.
  • Other plants that propagate through runners: Grass, Spider Plant, and Mint.
  • Asexual reproduction: A common method in plants to produce genetically identical offspring.

Additional Information:

  • Jasmine: Propagates through cuttings or layering.
  • Potato: Grows through tubers (underground storage stems).
  • Rose: Propagates through stem cuttings or grafting.
Q3.

Which of the following is the female germ cell in plants?

  • A.

    Cells outside the ovule

  • B.

    Cells in the centre of ovule

  • C.

    Egg cell

    ✓ Correct
  • D.

    Cell opposite to egg cell in an ovule

Answer & Solution

Correct option is C

The correct answer is (C) Egg cell.

Explanation:

  • In plants, the female germ cell is the egg cell (also called the ovum), which is located inside the embryo sac within the ovule.
  • During fertilization, the egg cell fuses with the male sperm cell to form a zygote, which develops into an embryo.

Information Booster:

  • The ovule is the female reproductive structure in flowering plants, found inside the ovary.
  • It contains the embryo sac, which houses the egg cell along with other cells like synergids, antipodal cells, and central cell.
  • After fertilization, the ovule develops into a seed, while the ovary develops into a fruit.

Additional Information:

  • Cells outside the ovule (A): Do not participate in fertilization.
  • Cells in the centre of ovule (B): Refers to the central cell, which forms the endosperm after fertilization.
  • Cell opposite to egg cell (D): Refers to antipodal cells, which have no direct role in fertilization.
Q4.
When an object is placed at the center of curvature (C) of a concave mirror, what is the nature of the image formed?
  • A.Enlarged and inverted
  • B.Highly diminished, point-sized
  • C.Real and inverted
    ✓ Correct
  • D.Virtual and erect

Answer & Solution

Correct option is C

The correct answer is (C) Real and inverted

Explanation:
• For a concave mirror, when an object is placed exactly at the Center of Curvature (C), the image is formed exactly at the Center of Curvature (C) as well.
• The light rays actually meet after reflection, making it a real image, and it forms below the principal axis, making it inverted.
• Notably, the image formed is exactly the same size as the object.

Information Booster:
• Concave Mirror Uses: Because of their converging nature, they are used in vehicle headlights, shaving mirrors, and by dentists to see enlarged images (when the object is placed close, between the pole and focus).
• Center of Curvature (C): It is the center of the hollow glass sphere of which the mirror is a part. The distance from the pole to C is the radius of curvature (R).

Additional Knowledge:
• Enlarged and inverted (Option A): This happens when the object is placed between the Center of Curvature (C) and the Principal Focus (F).
• Highly diminished (Option B): This occurs when the object is placed at infinity; the image forms at the focus (F).
• Virtual and erect (Option D): A concave mirror only forms a virtual, erect, and enlarged image when the object is placed very close to the mirror, between the Pole (P) and the Focus (F).
Q5.
Which rule helps to determine the direction of force acting on a current-carrying conductor in a magnetic field?
  • A.Ampere's rule
  • B.Faraday's law
  • C.Fleming's left-hand rule
    ✓ Correct
  • D.Right-hand rule

Answer & Solution

Correct option is C

The correct answer is (C) Fleming's left-hand rule

Explanation:
• Fleming's Left-Hand Rule states that if you stretch the thumb, forefinger, and middle finger of your left hand mutually perpendicular to each other:
• The Forefinger points in the direction of the Magnetic Field.
• The Middle finger points in the direction of the Current.
• The Thumb will then point in the direction of the Force (or motion) acting on the conductor.
• This rule governs the working principle of electric motors.

Information Booster:
• Maximum Force: The force experienced by the conductor is maximum when the direction of current is exactly perpendicular (90 degrees) to the magnetic field.
• Lorentz Force: The underlying physical phenomenon is the Lorentz force, where moving charges experience a magnetic force.

Additional Knowledge:
• Ampere's rule / Right-hand thumb rule (Option A & D): The Right-Hand Thumb Rule is used to find the direction of the magnetic field generated *around* a straight current-carrying conductor.
• Faraday's law (Option B): This law relates to electromagnetic induction (generating current from changing magnetic fields), not the physical force on a conductor.
Q6.
A young child is diagnosed with both myopia and hypermetropia in different eyes. What is the most appropriate corrective approach?
  • A.Using bifocal lenses in both eyes
  • B.Providing glasses with different lenses for each eye (concave for one, convex for the other)
    ✓ Correct
  • C.Providing identical convex lenses for both eyes
  • D.Using cylindrical lenses in both eyes

Answer & Solution

Correct option is B

The correct answer is (B) Providing glasses with different lenses for each eye (concave for one, convex for the other)

Explanation:
• Myopia (nearsightedness) occurs when the eyeball is too long, causing images to focus in front of the retina. It is corrected using a diverging concave lens.
• Hypermetropia (farsightedness) occurs when the eyeball is too short, causing images to focus behind the retina. It is corrected using a converging convex lens.
• Since the child has a different refractive error in each eye (a condition known as anisometropia), the spectacles must be customized. The myopic eye requires a concave lens, while the hypermetropic eye requires a convex lens.

Information Booster:
• Anisometropia: Having drastically different refractive powers in each eye can lead to amblyopia (lazy eye) in children if not corrected promptly, as the brain begins to ignore the blurrier image.
• Power of a Lens: Lens power is measured in Diopters (D). Myopic corrections have a negative (-) power, while hypermetropic corrections have a positive (+) power.

Additional Knowledge:
• Bifocal lenses (Option A): Bifocals are used for Presbyopia, an age-related condition where a single eye struggles with both near and distant vision. They contain both convex and concave segments in the same lens.
• Cylindrical lenses (Option D): These are used exclusively to correct Astigmatism, a condition caused by an irregularly curved cornea.
Q7.
A sound wave travels from air into water. How does its frequency, speed, and wavelength change as it crosses the boundary?
  • A.Its frequency increases, speed remains the same, and wavelength decreases
  • B.Its frequency decreases, speed decreases, and wavelength increases
  • C.Its frequency remains constant, speed decreases, and wavelength decreases
  • D.Its frequency remains constant, speed increases, and wavelength increases
    ✓ Correct

Answer & Solution

Correct option is D

The correct answer is (D) Its frequency remains constant, speed increases, and wavelength increases

Explanation:
• When a sound wave passes from one medium to another (e.g., air to water), its frequency remains constant because frequency is determined solely by the source of the sound, not the medium.
• The speed of sound is governed by the elasticity and density of the medium. Water is significantly more incompressible and elastic than air, causing the speed of sound to increase dramatically (from ~343 m/s in air to ~1480 m/s in water).
• According to the wave equation (v = f × λ), since frequency (f) is constant and speed (v) increases, the wavelength (λ) must also increase proportionally.

Information Booster:
• Sound in Solids: Sound travels even faster in solids (like steel) than in liquids because strong intermolecular forces allow mechanical waves to transfer energy more rapidly.
• Longitudinal Waves: Sound waves are mechanical longitudinal waves, requiring a material medium to propagate.

Additional Knowledge:
• Options A, B & C: Any option suggesting that frequency changes when changing mediums is fundamentally incorrect in wave physics. Options suggesting a decrease in speed ignore the mechanical properties of liquids vs. gases.
Q8.
What happens to the work done if the displacement becomes zero despite a force being applied?
  • A.The work done decreases.
  • B.The work done increases.
  • C.The work done is zero.
    ✓ Correct
  • D.The work done remains constant.

Answer & Solution

Correct option is C

The correct answer is (C) The work done is zero.

Explanation:
• In physics, work is defined as the product of the force applied to an object and the displacement caused by that force in the direction of the force.
• The mathematical formula is W = F × s × cos(θ), where W is work, F is force, and s is displacement.
• According to the formula, if the displacement (s) is strictly zero, any number multiplied by zero equals zero. Therefore, irrespective of how massive the force applied is, no mechanical work is done.

Information Booster:
• Real-world Example: If a person pushes against a rigid, unmoving brick wall for hours and gets exhausted, biologically they have spent energy, but from a strict physics standpoint, the work done on the wall is zero because the wall didn't move.
• Other Zero Work Scenarios: Work is also zero if the force applied is exactly perpendicular to the direction of displacement (since cos(90°) = 0), such as a porter carrying a load horizontally on his head.

Additional Knowledge:
• Options A, B & D: The concept of work in physics requires a non-zero displacement. It does not simply "decrease" or "remain constant" relative to the force applied if the object doesn't move.
Q9.
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?
  • A.Connect the appliance only to the neutral wire
  • B.Connect the appliance in parallel with existing appliances
    ✓ Correct
  • C.Connect the appliance only to the earth wire
  • D.Connect the appliance in series with existing appliances

Answer & Solution

Correct option is B

The correct answer is (B) Connect the appliance in parallel with existing appliances

Explanation:
• Domestic electrical wiring is universally done in a parallel configuration.
• In a parallel circuit, each appliance connects across the main supply lines (live and neutral). This ensures that every appliance receives the same full voltage (e.g., 220V in India) required for optimal operation.
• Furthermore, parallel wiring allows each appliance to have its own independent switch. If one appliance is turned off or burns out, it does not break the circuit for the other appliances.

Information Booster:
• Current Distribution: In a parallel circuit, the total current from the main supply divides among the branches based on the power rating (resistance) of each appliance.
• Overloading: While parallel circuits are standard, adding too many high-power appliances across a single line can draw excessive total current, leading to overloading and potential fire hazards.

Additional Knowledge:
• Series connection (Option D): If connected in series, the voltage would divide among the appliances, leading to dim lights and underpowered devices. Plus, if one fails, all stop working.
• Live, Neutral, Earth (Options A & C): An appliance requires a complete circuit across the Live and Neutral wires to function. The Earth wire is strictly for safety against electric shocks, not for completing operational circuits.
Q10.
Why are solids described as rigid in nature?
  • A.Their particles slide easily under applied external force
  • B.Their particles possess very low mass and volume
  • C.Their particles are closely packed with strong attraction
    ✓ Correct
  • D.Their particles move freely with weak mutual attraction

Answer & Solution

Correct option is C

The correct answer is (C) Their particles are closely packed with strong attraction

Explanation:
• The kinetic theory of matter dictates that in a solid state, the constituent particles (atoms, molecules, or ions) are packed tightly together in fixed positions.
• There are very strong intermolecular forces of attraction holding these particles in place, leaving negligible intermolecular spaces.
• Because the particles can only vibrate about their mean positions and cannot translate or flow, the entire structure strongly resists any change in shape when external force is applied, rendering the solid 'rigid'.

Information Booster:
• Compressibility: Due to the lack of space between particles, solids are highly incompressible.
• Definite Shape and Volume: The rigidity and fixed atomic positions give solids a definite shape and a definite volume, unlike liquids and gases.

Additional Knowledge:
• Particles sliding easily (Option A): This describes liquids, where intermolecular forces are weaker, allowing the substance to flow and take the shape of its container.
• Particles moving freely (Option D): This describes gases, where kinetic energy is high and intermolecular attraction is virtually negligible.
Q11.
Magnesium ribbon burns with:
  • A.A blue non-luminous flame
  • B.A bright white flame
    ✓ Correct
  • C.A yellow luminous flame
  • D.No visible flame

Answer & Solution

Correct option is B

The correct answer is (B) A bright white flame

Explanation:
• When a magnesium ribbon is ignited in the presence of air (specifically oxygen), it undergoes a highly exothermic combination reaction.
• It burns with a characteristic, intensely dazzling white flame.
• The product of this combustion is a powdery white ash called magnesium oxide (MgO). The reaction is: 2Mg(s) + O2(g) → 2MgO(s).

Information Booster:
• Pre-cleaning: Before burning, a magnesium ribbon must be cleaned with sandpaper. This removes the protective layer of basic magnesium carbonate that slowly forms on its surface when exposed to moist air, which would otherwise hinder ignition.
• Safety Precaution: The bright white light emits strong ultraviolet radiation, which can temporarily damage the retina; hence it should be viewed through dark glasses.

Additional Knowledge:
• Blue flame (Option A): Common in complete combustion of hydrocarbon gases (like an LPG stove) due to lack of unburnt carbon particles.
• Yellow luminous flame (Option C): Associated with incomplete combustion of hydrocarbons (like a candle), where glowing soot particles produce yellow light.
Q12.
Which property explains why the path of light is not visible when a beam passes through a true solution?
  • A.Particles are smaller than one nanometre
    ✓ Correct
  • B.Particles can be removed by filtration
  • C.Particles are heavier than solvent molecules
  • D.Particles settle down on standing still

Answer & Solution

Correct option is A

The correct answer is (A) Particles are smaller than one nanometre

Explanation:
• A true solution is a perfectly homogeneous mixture (e.g., salt dissolved in water).
• The solute particles in a true solution are extremely small, generally measuring less than 1 nanometer (10^-9 meters) in diameter.
• Because these particles are smaller than the wavelength of visible light, they cannot scatter a beam of light passing through the solution. Consequently, the path of light remains invisible.

Information Booster:
• Tyndall Effect: The scattering of a light beam by particles is called the Tyndall effect. It is prominent in colloids (like milk) and suspensions (like muddy water), where particles are larger (1 nm to 1000 nm).
• Stability: True solutions are highly stable; solute particles never settle at the bottom over time.

Additional Knowledge:
• Filtration (Option B): Solute particles in a true solution are so small they pass entirely through filter paper.
• Settling down (Option D): This is a characteristic of a 'suspension', where large unstable particles fall out of the liquid phase under gravity.
Q13.
Which change will promote micelle formation in a detergent solution?
  • A.Increasing detergent concentration above Critical Micelle Concentration(CMC)
    ✓ Correct
  • B.Lowering the temperature below Kraft point
  • C.Adding more water to dilute the solution
  • D.Decreasing detergent concentration below Critical Micelle Concentration(CMC)

Answer & Solution

Correct option is A

The correct answer is (A) Increasing detergent concentration above Critical Micelle Concentration(CMC)

Explanation:
• Micelles are aggregated clusters of surfactant molecules that form in a colloidal solution.
• This aggregation only occurs when the concentration of the detergent exceeds a specific threshold known as the Critical Micelle Concentration (CMC).
• Above the CMC, the hydrophobic tails of the detergent molecules group together away from water, while the hydrophilic heads face outward, creating the micelle structure necessary for trapping dirt.

Information Booster:
• Kraft Temperature (Kraft Point): Micelle formation also requires a minimum temperature called the Kraft point. Below this temperature, surfactants remain crystalline and do not form micelles.
• Hydrophobic and Hydrophilic: The dual nature of detergent molecules (amphiphilic) is what allows them to interact with both water and oils simultaneously.

Additional Knowledge:
• Option B: Lowering the temperature below the Kraft point prevents micelle formation, as the detergent precipitates out of the solution.
• Options C & D: Diluting the solution or decreasing the concentration pushes the system below the CMC, causing existing micelles to break apart into individual molecules.
Q14.
Which of the following statements is TRUE for all saturated hydrocarbons?
  • A.They are generally very reactive due to triple bonds.
  • B.They readily undergo addition reactions.
  • C.They contain at least one double bond.
  • D.They show substitution reactions rather than addition reactions.
    ✓ Correct

Answer & Solution

Correct option is D

The correct answer is (D) They show substitution reactions rather than addition reactions.

Explanation:
• Saturated hydrocarbons (alkanes) contain only single covalent bonds between carbon atoms. Because all carbon valencies are fully satisfied, they cannot simply "add" new atoms.
• Therefore, they primarily undergo substitution reactions, where an existing hydrogen atom is replaced (substituted) by another atom or group of atoms (such as halogens in the presence of sunlight).

Information Booster:
• Alkanes Formula: The general formula for saturated hydrocarbons is CnH2n+2.
• Chemical Stability: Alkanes are relatively unreactive towards acids, bases, and oxidizing agents under normal conditions, which is why they are sometimes called 'paraffins' (Latin for 'little affinity').

Additional Knowledge:
• Very reactive / Triple bonds (Option A): Alkynes possess triple bonds and are highly reactive unsaturated hydrocarbons.
• Addition reactions (Option B) & Double bonds (Option C): Alkenes contain double bonds (unsaturated) and readily undergo addition reactions (like hydrogenation) to break the double bond and add new atoms.
Q15.
Which of the following compounds has a formula unit mass of 100 u?
  • A.MgO
  • B.CaCl2
  • C.Na2CO3
  • D.CaCO3
    ✓ Correct

Answer & Solution

Correct option is D

The correct answer is (D) CaCO3

Explanation:
• The formula unit mass of a substance is the sum of the atomic masses of all atoms in a formula unit of a compound.
• To calculate the mass of Calcium Carbonate (CaCO3):
- Atomic mass of Ca = 40 u
- Atomic mass of C = 12 u
- Atomic mass of O = 16 u
• Calculation: 40 + 12 + (3 × 16) = 40 + 12 + 48 = 100 u.

Information Booster:
• Calcium Carbonate: It is the primary component of limestone, marble, chalk, and eggshells. It is widely used as a building material and in the manufacture of cement.
• Unified Mass (u): Atomic masses are expressed in unified atomic mass units (u), replacing the older 'amu'. It is defined as one-twelfth of the mass of a carbon-12 atom.

Additional Knowledge:
• MgO (Option A): Mg(24) + O(16) = 40 u.
• CaCl2 (Option B): Ca(40) + Cl2(2 × 35.5) = 40 + 71 = 111 u.
• Na2CO3 (Option C): Na2(2 × 23) + C(12) + O3(3 × 16) = 46 + 12 + 48 = 106 u.

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