Physics for Railways

What you'll learn

A from-scratch, Class 10 level guide to the physics every RRB NTPC aspirant needs: motion and its equations, Newton's laws of force, work-energy-power, and the basics of light and electricity - with SI units, a worked train example, and a quick-revision table.

This chapter has

Physics for Railways — solved practice questions

8 Railways General Science questions with step-by-step solutions. Attempt each, then reveal the answer.

1. Q1easy

   What is the SI unit of electric current?

   • AVolt
   • BWatt
   • CAmpere
   • DOhm
   Show answer & solution

   Correct answer: (C) Ampere

   The ampere (A) is the SI base unit of electric current, named after André-Marie Ampère.

2. Q2easy

   Which physical quantity is measured in newtons?

   • AForce
   • BEnergy
   • CPower
   • DPressure
   Show answer & solution

   Correct answer: (A) Force

   Force is measured in newtons (N); one newton is the force needed to accelerate 1 kg by 1 m/s².

3. Q3easy

   A body moving with uniform velocity has an acceleration of:

   • APositive constant value
   • BZero
   • CNegative constant value
   • DIncreasing value
   Show answer & solution

   Correct answer: (B) Zero

   Uniform velocity means constant speed and direction, so there is no change in velocity and acceleration is zero.

4. Q4medium

   The speed of light in vacuum is approximately:

   • A3 × 10^6 m/s
   • B3 × 10^5 m/s
   • C3 × 10^10 m/s
   • D3 × 10^8 m/s
   Show answer & solution

   Correct answer: (D) 3 × 10^8 m/s

   Light travels in vacuum at about 3 × 10^8 metres per second, roughly 300,000 km/s.

5. Q5easy

   Which law states that for every action there is an equal and opposite reaction?

   • ANewton's first law
   • BNewton's second law
   • CNewton's third law
   • DLaw of gravitation
   Show answer & solution

   Correct answer: (C) Newton's third law

   Newton's third law of motion states that every action has an equal and opposite reaction.

6. Q6medium

   The commonly used unit of electrical energy in households (as billed) is the:

   • AJoule
   • BKilowatt-hour
   • CWatt
   • DNewton-metre
   Show answer & solution

   Correct answer: (B) Kilowatt-hour

   Household electricity is billed in kilowatt-hours (kWh), also called the 'unit' of electricity.

7. Q7medium

   What kind of mirror is used as a rear-view mirror in vehicles?

   • AConvex mirror
   • BConcave mirror
   • CPlane mirror
   • DCylindrical mirror
   Show answer & solution

   Correct answer: (A) Convex mirror

   A convex mirror gives an erect, diminished image and a wider field of view, ideal for rear-view mirrors.

8. Q8easy

   The bending of light as it passes from one medium to another is called:

   • AReflection
   • BDiffraction
   • CDispersion
   • DRefraction
   Show answer & solution

   Correct answer: (D) Refraction

   Refraction is the change in direction of light when it moves between media of different densities.

Want the full set? Practise all 15 Physics for Railways questions →