Railway Science English is a General Science guide for Railway Exams 2026, published by ADITYA RANJAN PUBLICATIONS. It covers Physics, Chemistry, and Biology, featuring the "Top 500 Topicwise Ques. Detailed Explanation asked From 2024 to 2025". The content is useful for exams like ALP, TECHNICIAN, GROUP D, NTPC, JE, and RPF.
Physics Topics and Key Concepts Covered:
Units & Dimensions (14 questions):
Fundamental units are used to measure fundamental physical quantities.
A system of units includes both fundamental and derived units.
SI units include: Length is Meter (m), Energy is Joule (J), Frequency is Hertz (Hz), and Pressure is Pascal (Pa) or Nm⁻².
Dimensional formula for Density.
One carat is equal to 200 milligrams.
Motion (16 questions):
Distance is the total path length covered.
Displacement is zero when the initial and final positions are the same.
An object in uniform motion follows a straight line path (rectilinear motion).
Special theory of relativity applies to inertial frames.
Force (14 questions):
Gravitational force is a non-contact force controlling celestial motion.
Newton's first law (law of inertia) states an object remains in its state of rest or motion unless an external force is applied.
Newton's second law is F=ma.
Impulse is the product of force and time, equal to the change in momentum.
An object bounces back in water because the buoyancy force is greater than the gravitational force.
Work, Energy & Power (14 questions):
1 erg equals 10^-7J.
Work is done when a force causes displacement in the direction of the force.
Mechanical energy is the sum of Potential Energy (due to position) and Kinetic Energy (due to motion).
Kinetic Energy (KE) depends on mass and the square of velocity.
Power is the rate of doing work or energy transfer.
Gravity (13 questions):
The radius of the Earth is approximately 6400 km.
Gravitational force is directly proportional to the product of masses and inversely proportional to the square of the distance between them.
The acceleration due to gravity ('g') is more at the poles than at the equator.
Mass is a scalar quantity, while weight is a vector quantity dependent on gravity.
The gravitational force between the Moon and the Earth causes tides.
Sound & Waves (8 questions):
Waves in a string are produced by periodic oscillatory motion.
The crest of a wave is the point of maximum disturbance.
Sound waves in air are an example of longitudinal waves.
If air temperature increases, the speed of sound and the minimum distance to hear an echo both increase.
Infrasound frequencies are below 20 Hz.
Sonar uses acoustic waves to locate objects in the ocean.
Electric Current (28 questions):
According to Ohm's law, a voltage-current graph is a straight line.
Resistance opposes the flow of current.
Lowest resistance is achieved with short length and large cross-sectional area.
In most conductors, resistance increases with temperature.
Removing a resistor in a series circuit causes the current to become zero.
Total resistance in a parallel combination is always less than the minimum resistance.
Electric appliances like irons and toasters are based on the thermal effect of electric current.
A rheostat is a variable resistor.
A fuse prevents excessive current flow.
Magnetism (24 questions):
Earth's magnetism is caused by the dynamo effect.
A compass needle deflects near a bar magnet because the needle is a small bar magnet itself.
Magnetic field lines form closed loops, emerge from the north pole, enter the south pole outside the magnet, and do not intersect.
Fleming's left hand rule determines the force on a current-carrying conductor in a magnetic field.
Fleming's right hand rule determines the direction of induced current.
The strength of the magnetic field inside a current-carrying solenoid is the same at all points.
A charged particle moving in a uniform magnetic field follows a helical path.
Electromagnetic Induction (5 questions):
Self-induction is the induction of EMF in a coil due to a change in its own current.
Induced current is maximum when the coil's motion is 90^\circ (perpendicular) to the magnetic field.
An electric motor converts electrical energy into mechanical energy.
Potential difference is induced in a closed coil when either the bar magnet or the coil moves relative to the other.
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