Ans: Class 11 Physics Chapter 2 is based on units and measurement. Students will study the different units and measurement systems. They will study different units used for measuring length, time, and distance. The important topics given in Class 11 Physics Chapter 2 include absolute errors, SI units, significant figures, and dimensional analysis. It is an important chapter for the exams. Students can understand the topics given in Class 11 Physics Chapter 2 from the notes given on Vedantu app and website.
The definition, agreement, and practical use of units of measurement have played a crucial role in human endeavour from early ages up to the present. A multitude of systems of units used to be very common. Now there is a global standard, the International System of Units (SI), the modern form of the metric system.
Measurement Units And Dimensions Pdf Download
In physics and metrology, units are standards for measurement of physical quantities that need clear definitions to be useful. Reproducibility of experimental results is central to the scientific method. A standard system of units facilitates this. Scientific systems of units are a refinement of the concept of weights and measures historically developed for commercial purposes.[3]
Science, medicine, and engineering often use larger and smaller units of measurement than those used in everyday life. The judicious selection of the units of measurement can aid researchers in problem solving (see, for example, dimensional analysis).
At some point in time though, the need to relate the two units might arise, and consequently the need to choose one unit as defining the other or vice versa. For example, an inch could be defined in terms of a barleycorn. A system of measurement is a collection of units of measurement and rules relating them to each other.
As science progressed, a need arose to relate the measurement systems of different quantities, like length and weight and volume. The effort of attempting to relate different traditional systems between each other exposed many inconsistencies, and brought about the development of new units and systems.
Historically many of the systems of measurement which had been in use were to some extent based on the dimensions of the human body. As a result, units of measure could vary not only from location to location but from person to person.
Both the imperial units and US customary units derive from earlier English units. Imperial units were mostly used in the British Commonwealth and the former British Empire. US customary units are still the main system of measurement used in the United States outside of science, medicine, many sectors of industry, and some of government and military, and despite Congress having legally authorised metric measure on 28 July 1866.[7] Some steps towards US metrication have been made, particularly the redefinition of basic US and imperial units to derive exactly from SI units. Since the international yard and pound agreement of 1959 the US and imperial inch is now defined as exactly 0.0254 m, and the US and imperial avoirdupois pound is now defined as exactly 0.45359237 kg.[8]
While the above systems of units are based on arbitrary unit values, formalised as standards, some unit values occur naturally in science. Systems of units based on these are called natural units. Similar to natural units, atomic units (au) are a convenient system of units of measurement used in atomic physics.
One example of the importance of agreed units is the failure of the NASA Mars Climate Orbiter, which was accidentally destroyed on a mission to Mars in September 1999 instead of entering orbit due to miscommunications about the value of forces: different computer programs used different units of measurement (newton versus pound force). Considerable amounts of effort, time, and money were wasted.[11][12]
Independent units can be applied to areas and volumes retroactively. To recalculate a previously measured area or volume with a newly set unit of measure, just click Recalculate. All measurements on the page will be recalculated with the current units of measurement.
Question 13. Name four units used in the measurement of extremely short distances.Answer: 1 micron (1 p) = 10-6 m1 nano metre (1 nm) = 10-9 m1 angstrom (1 A) = 10-10 m1 fermi (1 f) = 10-15 m.
Question 3. It is known that the period T of a magnet of magnetic moment M vibrating in a uniform magnetic field of intensity B depends upon M, B and I where I is the moment of inertia of the magnet about its axis of oscillations. Show thatAnswer: We first note that the dimension of I are [ML2]. Also the magnetic moment has the units Am2 so that its dimensions can be written as [AL2] where A stands for the dimensions of the electric current. Finally the magnetic field vector B has the units newton (per ampere metre) so that its dimensions can be written as
Need for measurement: Units of measurement; systems of units; SI units, fundamental and derived units. significant figures. Dimensions of physical quantities, dimensional analysis and its applications.
These worksheets review the customary and metric units for measuring length, weight, capacity and temperature. The object is to improve familiarity with the different units and provide practice converting measurements between different units of the same system (e.g. inches to feet). Conversion between systems is not covered until grade 5.
Of course, any provider knows that the inside measurements and outside measurements are going to differ. While the lengths of outside walls are going to give you a good idea of your overall dimensions, the lengths of the internal walls will help you determine your actual usable space.
Follow a two-step process to arrive at the area of rectangles with the length and width in different units. The first step is to convert the dimensions to the specified unit, and the next one is to use the converted measures in the formula. 2ff7e9595c
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