 # CBSE Class 11 Physics NCERT Solutions: Chapter 2, Units and Measurement

Sep 18, 2018 11:01 IST Units and Measurement: NCERT Solutions

Any exam preparation is a rigorous process which requires an overall understanding of the concepts and basics discussed in a chapter. If we talk about the Class 11 Physics, then one thing to be noticed is that Physics in class 11 is demanding on the numericals. Almost all the chapters involve numericals and derivations. Students should learn the derivations step by step and understand the concepts involved in each of them. On the other hand, numericals have to be practiced well after absorbing the concepts, basic laws and derivations.

Read NCERT books and solve questions given at the end of each chapter

A significant role is played by the NCERT books as these books explain each topic in detail  but simple language to help students understand each and every line easily. Also these books offer a number of problems which students can practice to assess their learning and prepare for the examinations. Hence, all the students prefer studying from NCERT books.

Class 11 Physics NCERT solutions for chapter - Units and Measurement:

Here we are providing NCERT solutions for CBSE Class 11 Physics Chapter 2, Units and Measurement. Students can refer these NCERT solutions to check the correctness of their own answers and thus assess their level of understanding about each topic. All these model solutions have been prepared by the subject experts and involve appropriate concepts.

Main topics discussed in Class 11 Physics chapter- Units and Measurement are:

• The international system of units
• Measurement of length
• Measurement of mass
• Measurement of time
• Accuracy, precision of instruments and errors in measurement
• Significant figures
• Dimensions of physical quantities
• Dimensional formulae and dimensional equations
• Dimensional analysis and its applications.

CBSE Class 11 Physics Syllabus 2018 - 2019

Some of the questions and their solutions from NCERT Solutions for Class 11: Units and Measurement, are as follows:

Q. E×plain this statement clearly:

“To call a dimensional quantity ‘large’ or ‘small’ is meaningless without specifying a standard for comparison” . In view of this, reframe the follow statements wherever necessary:

(a) atoms are very small objects

(b) a jet plane moves with great  speed

(c) the mass of Jupiter is very large

(d) the air inside this room contains a large number of molecules

(e) a proton is much more massive than an electron

(f) the speed of sound is much smaller than the speed of light.

Sol. The given statement is true because a dimensionless quantity may be large or small in comparison to some standard reference. For example, the coefficient of friction is dimensionless. The coefficient of sliding friction is greater than the coefficient of rolling friction, but less than static friction.

(a) An atom is very small object in comparison to a soccer ball

(b) A jet plan moves with a speed with a speed greater than that of a bicycle.

(c) Mass of Jupiter is very large as compared to the mass of a cricket ball.

(d) The air inside this room contains a large number of molecules as compared to that present in a geometry box.

(e) A Proton is more massive than an electron.

(f) Speed of Sound is less than the speed of light.

Q. A new unit of length is chosen such that the speed of light in vacuum is unity. What is the distance between the Sun and the Earth in term of the new unit if light takes 8 min and 20 s to cover this distance?

Sol. Distance between the Sun and the Earth:

=Speed of light × Time taken by light to cover the distance

Given that in the new unit, speed of light = 1 unit

Time taken, t= 8 min 20 s = 500 s

Distance between the Sun and the Earth = 1 × 500 =500 units

Download all the NCERT solutions for Class 11: Units and Measurement, from the following link:

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