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RRB ALP GK Questions 2026

General Science is the knowledge section of RRB ALP under CEN 01/2026. The CEN defines it as Physics, Chemistry and Life Sciences of Class 10 level in CBT-1, and CBT-2 Part A adds Basic Science and Engineering: units and measurements, mass, weight and density, work, power and energy, speed and velocity, heat and temperature, basic electricity, levers and simple machines, engineering drawing, occupational safety and health, environment education and IT literacy. The notes on this page are GK24's topic-wise GK notes for RRB ALP, written as short facts, formulas and tables so that a topic can be revised in one sitting. Physics notes cover motion, force, gravitation, work and energy, sound, light, electricity and magnetism; Chemistry notes cover matter, atoms and molecules, chemical reactions, acids, bases and salts, metals and non-metals, carbon compounds and the periodic table; Life Sciences notes cover the cell, life processes, control and coordination, reproduction, heredity, diseases and the environment. Topics that appear in both CBT-1 General Science and CBT-2 Basic Science and Engineering, such as units, energy, heat and electricity, are marked so that one reading serves two papers. Each note ends with the previous-year questions asked on it, and the quizzes on this site draw from the same topics, so a weak quiz score points back to the note to reread.

RRB ALP GK Questions with Answers

Q142.General ScienceAsked in: NDA · NDA-II 2026, GATMedium

Two astronauts X and Y float in deep space far from external forces. Initially, they are at rest relative to one another. X throws a tool towards Y. Consider the two astronauts and the tool as one system. Which one of the following statements is correct ?

  1. A.The centre of mass of the system moves towards Y.
  2. B.X moves and the centre of mass of the system follows him.
  3. C.The centre of mass follows the tool.
  4. D.The centre of mass remains fixed.
Show answer
Correct answer: D. The centre of mass remains fixed.

With no external force on the system, its centre of mass cannot start moving. The throw is an internal force: X pushes the tool forward and the tool pushes X backward with an equal and opposite force (Newton's third law).

Q143.General ScienceAsked in: CDS · CDS-I 2017, GKMedium

Suppose voltage V is applied across resistance R. The power dissipated in the resistance is P. Now the same voltage V is applied across a parallel combination of three equal resistors each of resistance R. Then the power dissipated in the second case will be

  1. A.P
  2. B.3P
  3. C.P/3
  4. D.2P/3
Show answer
Correct answer: B. 3P

Three equal resistors R in parallel have a combined resistance of R/3, and at the same voltage the power, V²/R, becomes three times as large.

Q144.General ScienceAsked in: NDA · NDA-II 2019, GATEasy

A car starts from Bengaluru, goes 50 km in a straight line towards south, immediately turns around and returns to Bengaluru. The time taken for this round trip is 2 hours. The magnitude of the average velocity of the car for this round trip

  1. A.is 0.
  2. B.is 50 km/hr.
  3. C.is 25 km/hr.
  4. D.cannot be calculated without knowing acceleration.
Show answer
Correct answer: A. is 0.

Average velocity is total displacement divided by time, and the car ends where it started, so its displacement is zero.

Q146.General ScienceAsked in: NDA · NDA-I 2022, GATEasy

The magnetic field produced by a current-carrying straight wire at a point outside the wire depends

  1. A.inversely on the distance from it
  2. B.directly on the distance from it
  3. C.inversely at short distances and directly at large distances from it
  4. D.directly on the distance (at short distances) and inversely on the distance (at long distances) from it
Show answer
Correct answer: A. inversely on the distance from it

Outside a long straight wire, the field is B = μ₀I/(2πr), so doubling the distance halves the field. This result follows from Ampère's circuital law, or from the Biot–Savart law applied to a long wire.

Q147.General ScienceAsked in: NDA · NDA-II 2025, GATEasy

Which one of the following statements about surface tension is correct?

  1. A.It increases when temperature increases
  2. B.It decreases when temperature increases
  3. C.It will remain same with increase or decrease of temperature
  4. D.It will always decrease with increase or decrease of temperature
Show answer
Correct answer: B. It decreases when temperature increases

Heating weakens the attraction between the molecules of a liquid, so its surface pulls less tightly. Surface tension arises because molecules at the surface are pulled inward by their neighbours, making the surface behave like a stretched skin.

Q148.General ScienceAsked in: NDA · NDA-I 2026, GATEasy

It has been observed that a mirror always forms the image between the pole and the focus, irrespective of the location of the object. Which one of the following is correct in respect of the nature of the mirror?

  1. A.It is a plane mirror.
  2. B.It is a convex mirror.
  3. C.It is a concave mirror of small focal length.
  4. D.It is a concave mirror of large focal length.
Show answer
Correct answer: B. It is a convex mirror.

For any real object, a convex mirror forms a virtual, erect and smaller image behind the mirror, between the pole and the focus.

Q149.General ScienceAsked in: NDA · NDA-II 2026, GATHard

A heating filament and an ideal resistor of fixed value are connected in series with a DC voltage source. After some time, the filament has reached its operating point so that the current in the circuit is steady. Which one of the following is correct?

  1. A.The steady current is larger than the initial value.
  2. B.The steady voltage across the ideal resistor decreases as compared to its initial value.
  3. C.Overall resistance of the circuit decreases.
  4. D.Power dissipation through the filament increases as compared to its initial value.
Show answer
Correct answer: B. The steady voltage across the ideal resistor decreases as compared to its initial value.

A metal filament's resistance rises as it heats up, so the current falls and the resistor gets a smaller share of the voltage.

Q151.General ScienceAsked in: NDA · NDA-I 2021, GATEasy

The image we see in plane mirror is

  1. A.real and thus can be photographed.
  2. B.virtual and nearer than the object.
  3. C.virtual and is laterally inverted.
  4. D.real but cannot be photographed.
Show answer
Correct answer: C. virtual and is laterally inverted.

A plane mirror forms an image behind the mirror where light only seems to come from, with left and right swapped.

Q152.General ScienceAsked in: NDA · NDA-I 2022, GATEasy

What is the current required to light a 60 W incandescent bulb in a domestic supply of 240 V?

  1. A.0.5 A
  2. B.0.25 A
  3. C.1.0 A
  4. D.5.0 A
Show answer
Correct answer: B. 0.25 A

Electric power equals voltage times current, so the current is 60 W ÷ 240 V = 0.25 A. The relation P = VI comes straight from the definitions: voltage is energy per unit charge and current is charge per second, so their product is energy per second, or power.

Q153.General ScienceAsked in: NDA · NDA-II 2026, GATMedium

A hollow prism is filled with water of refractive index 1.34 and white light is incident on the prism. The white light is assumed to have wavelengths ranging from 4020 Å to 6700 Å. What is the corresponding wavelength range in water?

  1. A.3000 Å to 5000 Å
  2. B.4020 Å to 6700 Å
  3. C.5000 Å to 7000 Å
  4. D.5386 Å to 8978 Å
Show answer
Correct answer: A. 3000 Å to 5000 Å

When light enters a denser medium, its wavelength is divided by the refractive index of that medium. The frequency of light is fixed by its source and does not change on refraction.

Q154.General ScienceAsked in: NDA · NDA-II 2018, GATMedium

A stainless steel chamber contains Ar gas at a temperature T and pressure P. The total number of Ar atoms in the chamber is n. Now Ar gas in the chamber is replaced by CO₂ gas and the total number of CO₂ molecules in the chamber is n/2 at the same temperature T. The pressure in the chamber now is P'. Which one of the following relations holds true? (Both the gases behave as ideal gases)

  1. A.P' = P
  2. B.P' = 2P
  3. C.P' = P/2
  4. D.P' = P/4
Show answer
Correct answer: C. P' = P/2

For an ideal gas in a fixed volume at a fixed temperature, pressure is proportional to the number of molecules, so half the molecules give half the pressure.

Q155.General ScienceAsked in: NDA · NDA-II 2019, GATMedium

A solid disc and a solid sphere have the same mass and same radius. Which one has the higher moment of inertia about its centre of mass?

  1. A.The disc
  2. B.The sphere
  3. C.Both have the same moment of inertia
  4. D.The information provided is not sufficient to answer the question
Show answer
Correct answer: A. The disc

About an axis through the centre, a solid disc has I = ½MR² while a solid sphere has I = ⅖MR², and ½ is larger than ⅖.

Q156.General ScienceAsked in: NDA · NDA-II 2026, GATMedium

In a carrom game, a striker of mass 15 g hits a coin of mass 5 g head on and the coin moves with a speed of 0.36 m/s. If the time of contact between the striker and the coin is 3 milliseconds, then what is the average force applied by the striker on the coin?

  1. A.0.72 N
  2. B.0.60 N
  3. C.0.54 N
  4. D.0.30 N
Show answer
Correct answer: B. 0.60 N

Average force equals the change in momentum of the coin divided by the time of contact.

Q157.General ScienceAsked in: NDA · NDA-I 2026, GATMedium

One year at a planet is 8 times as large as compared to the one year at the Earth. Which one of the following is correct about the planet's orbit?

  1. A.The semimajor axis of the planet's orbit is same as that of the Earth.
  2. B.The semimajor axis of the planet's orbit is twice as compared to that of the Earth.
  3. C.The semimajor axis of the planet's orbit is thrice as compared to that of the Earth.
  4. D.The semimajor axis of the planet's orbit is four times as compared to that of the Earth.
Show answer
Correct answer: D. The semimajor axis of the planet's orbit is four times as compared to that of the Earth.

Kepler's third law says the square of a planet's orbital period is proportional to the cube of the semimajor axis of its orbit.

Q158.General ScienceAsked in: NDA · NDA-II 2026, GATHard

A biconvex lens is made of a material of refractive index 2 such that the ratio of the radii of curvature of its two faces is 1 : 2. A point source in air is placed on the principal axis of this lens at a distance u from the lens. Which one of the following is correct if the image is formed exactly at the same distance as that of the point source? (where R is the radius of curvature of the first face)

  1. A.u = R
  2. B.u = 2R
  3. C.2u = 3R
  4. D.3u = 4R
Show answer
Correct answer: D. 3u = 4R

A convex lens forms an image at the same distance as the object only when the object sits at 2f, and here 2f works out to 4R/3.

Q159.General ScienceAsked in: UPSC CAPF · CAPF 2019, Paper IEasy

Which one of the following is NOT true for an electromagnetic wave ?

  1. A.Electromagnetic wave transports energy and momentum
  2. B.Electromagnetic wave can be polarized and reflected
  3. C.Electromagnetic wave is longitudinal
  4. D.Electromagnetic wave propagation is described by the varying electric and magnetic fields
Show answer
Correct answer: C. Electromagnetic wave is longitudinal

Electromagnetic waves are transverse, not longitudinal, so this statement is false. In an electromagnetic wave the electric field and the magnetic field oscillate at right angles to each other and both at right angles to the direction in which the wave travels.

Q160.General ScienceAsked in: NDA · NDA-I 2024, GATMedium

The relative atomic mass of boron (which exists in two isotopic forms ¹⁰B and ¹¹B) is 10.81. What will be the abundance of ¹⁰B and ¹¹B, respectively (consider a sample of 100 atoms)?

  1. A.19% and 81%
  2. B.81% and 19%
  3. C.38% and 62%
  4. D.62% and 38%
Show answer
Correct answer: A. 19% and 81%

Only this split of boron-10 and boron-11 gives an average atomic mass of 10.81. The relative atomic mass of an element is the average of its isotopes' masses, each weighted by how common it is.