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Physical World and Measurement for IIT JEE 2020 Exam

IIT/JEE2020 Published on 15 February 2020

The IIT JEE main exam will occur in between 3rd to 9th April in 2020. The application for filling the forms will start soon from 7th February till 7th March 2020. The result of the exam every year comes out around 30th April every year.

Physical World and Measurement is one of the most important topic for all the competitive exam such as IIT JEE 2020, NEET 2020 etc.

A large number of students are preparing for the exam to clear it. But while doing the preparation, the student always thinks that the syllabus is vast and time is less.

Chapter-1: Physical World

All the natural Phenomena follow some of the other physical laws and constitute the physical world around human beings. That is why Einstein truly said that “The most incomprehensible thing about the world is that it is comprehensible”.


Physics one of the basic stream of Natural Sciences and its meaning is ‘Nature’. Its Sanskrit meaning is “Bhautiki” which means “Study of Physical World”.

Basic Principal:

  1. To understand all the fundamental natural laws or forces as a unit i.e. Unification.
  2. To derive the properties of the different natural complex phenomenon from its individual simple interactions i.e. reduction.


The scope of the physics can be widely seen in two aspects:

  1. The Macroscopic view includes the study of the different phenomenon at laboratory, terrestrial or astronomy level.
  2. The Microscopic view includes the study of phenomena related to atoms, molecules and nuclear.

Fundamental Forces of Nature:

  • Gravitational Force: Mutual attraction force. 
  • It is the weakest force out of the four natural fundamental forces.
  • Its range is infinite and observed by all the objects present in the universe.
  • Electromagnetic Force: Force between charged particles.
  • ts range is also infinite.
  • Strong Nuclear Force: Force that puts Proton and Neutrons together in a nucleus.
  • Its range is short approx 10-15m.
  • Weak Nuclear Force: Forces related to some nuclear processes.
  • Its range is very short approx 10-16m


Law of Conservation: 

  • The conservation law in physics can be given for energy, mass, angular momentum, etc.
  • The law is governed by the theory given by Einstein i.e. E=mc2. Here, m=mass; c= speed of light; E= Energy.

Chapter-2: Units and Measurements


It is a universally accepted standard to measure any unknown quantity. 

The units can be broadly classified into two types:

  • Fundamental Units: like meter for length, second for time, etc.

  • Derived Units: This type of unit can be defined in terms of fundamental units like speed, acceleration, voltage, power etc.

Derived Formula for Speed:

Speed= Distance /Time

          = L/T

         = meter/ second

         = [msec-1] basic S.I. Unit


It is the process of assigning a numerical value to the physical parameters of any event or object so that it can be made comparable in physical space.

Different systems of units for Measurement:

  1. CGS ( Centimeter- Gram- Second ) Unit
  2. FPS ( Foot- Pound – Second) Unit
  3. MKS( Meter- Kilogram- Second) Unit
  4. SI (International Standard) Unit: This has 7 basic units like second(s) for time, meter (m) for length, kilogram(kg) for mass, ampere (A) for current, Kelvin (K) for temperature, mole (mol) for amount of substance and candela (Cd) for intensity. 

Errors in Measurement:

The uncertainty of measuring any object or event through a measuring instrument is termed as an error in measurement. It can be of following types:

  • Systematic Errors like instrumental errors
  • Random Errors like errors in signs.
  • Least Count Errors are the smallest value measured by a particular measuring instrument like 0.01cm for Vernier Calipers. 

All The Best To All The IIT JEE 2020 Aspirants!

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