Class 11 Physics Chapter 2 Units and Measurement Notes

Chapter 2 Units and Measurement

Units and Measurements is the second chapter of Year 11 Physics. NCERT notes for Class 11 Physics Chapter 2 are critical to understanding how different units are measured and converting measurements to the same units. With the help of NCERT notes, students can solve text questions given after each topic.

In this article, we have provided NCERT notes for Class 11 Chapter 2 Physics and important topics. Scroll down to learn more!

CBSE CLASS 11th PHYSICS CH-2

Points to Remember

Below we have provided some of the important points to remember for NCERT Class 11 Physics Chapter 2 to ace your exams:

1. Unit: Measurement of any physical quantity is expressed in terms of an internationally accepted certain basic standard called unit.

2. Fundamental Units:

S.No.	Physical Quantity	SI Unit	Symbol
1	Length	Metre	M
2	Mass	Kilogram	Kg
3	Time	Second	S
4	Electric Current	Ampere	A
5	Temperature	Kelvin	K

3. Supplementary Units:

S.No.	Physical Quantity	SI Unit	Symbol
1	Plane Angle	radian	r
2	Solid Angle	Steradian	Sr

 

Topics and Sub-topics

Units and measurements are concepts used in mathematics and science. The topics covered in this chapter are necessary to properly address questions about units and measurements. Also, students must first make all units uniform before solving the problem. Sometimes this can be confusing. So, solving the Vidyakul sample problems helps students remember the formulas and apply them correctly.

Vidyakul provides answers to all questions from the CBSE Class 11 Chapter 2 Physics Textbook based on the latest program. Students can solve these problems for free on the Vidyakul platform and get good grades. 

Below we have provided the list of topics included in CBSE Class 11 Physics Chapter 2:

Sr. No.	Topic Name
2.1	Introduction
2.2	The International System of Units
2.3	Measurement of Length
2.4	Measurement of Mass
2.5	Measurement of Time
2.6	Accuracy, Precision of Instruments and Errors in Measurement
2.7	Significant Figures
2.8	Dimensions of Physical Quantities
2.9	Dimensional Formulae and Dimensional Equations
2.10	Dimensional Analysis and Its Applications

Few Important Questions

• What is a ‘Unit of measurement’?

A standard amount of a physical quantity, such as length, mass, energy, etc, specified multiples of which are used to express magnitudes of that physical quantity is called a unit of measurement.

• What is the definition of ‘Speed’?

The ratio of the distance traveled by an object (regardless of its direction) to the time required to travel that distance.

• What is ‘Relative error’?

Relative error: When used as a measure of precision, is the ratio of the absolute error of a measurement to the measurement being taken.

Practice Questions

1. Provide an Explanation for this statement:
   “To call a dimensional quantity ‘large’ or ‘small’ is meaningless without specifying a
   standard for comparison”. Reframe the following statements, in view of this :
   (a) atoms are small structures
   (b) a jet plane travels with a maximum speed
   (c) Jupiter’s mass is very large
   (d) the air contains a large number of molecules
   (e) a proton massive than an electron
   (f) the speed of sound is smaller than the speed of light.

2. Let’s suppose a unit of length is chosen such that the speed of light in the vacuum is unity. What will be the distance and displacement between the Sun and the Earth in terms of the new unit if light takes 8 min and 20 s to cover this distance?

Which is the most precise device for measuring length :
(a) vernier calipers with 20 divisions on the sliding scale?
(b) a screw gauge of pitch 1 mm and 100 divisions on the circular scale?
(c) an optical instrument that can measure length to within a wavelength of light?

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