(c) 1.9 xlO12 Chapter 2 Units and Measurements . One unified atomic mass unit is approximately the mass of one nucleon (either a single proton or neutron) and is numerically equivalent to 1 g/mol. It is defined as one- twelfth of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state. Physics Notes Class 11 CHAPTER 2 UNITS AND MEASUREMENTS The comparison of any physical quantity with its standard unit is called measurement. Hence energy and work has same physical dimensional form. 56100 mm c. 3.7 km Photon is a quantum of radiation with energy E = hv, where v is frequency and h is Planck’s constant. Why do we have different units for the same physical quantity? Hence on rounding off 2.735 to 3 significant figures, it would be 2.74. Q14. Q40. Write the dimensional formula of (i) w and (ii) k So it is most precise. (a) 1.4 m± 0.4 m CBSE Class 11 Physics Worksheet - Unit and Measurement (1) CBSE,CCE and NCERT students can refer to the attached file. Sol: (a), Q6. Physics is a quantitative science, based on measurement of physical quantities.Certain physical quantities have been chosen as fundamental or base quantities. Download MCQs for Class 11 Physics with answers in PDF download format for important topics in Grade/ Class 11 Physics based on 2021 CBSE| NCERT | KVS syllabus and pattern. How much will 5J measure in this new system? Calculate at what size it will appear when seen through the same telescope. All given measurements are correct upto two decimal places. Become our. Key concept: Accuracy describes the nearness of a measurement to the standard or true value, i.e. Students can download free printable worksheets for practice, topic wise questions for all chapters. Due to atmospheric fluctuations, eye cannot resolve objects smaller than 1 arc minute. Q24. Sol: (a) D = b θ (2.1) Having determined D, we can employ a similar method to determine the size or angular diameter of the planet. We have covered all the Class 11 Physics important questions and answers in the worksheets which are included in CBSE NCERT Syllabus. Then 1 mL of this solution is diluted to 20 mL by adding alcohol. (a). If you are a student of Class 11 who is using NCERT Textbook to study Physics, then you must come across chapter 2 Units And Measurement After you have studied lesson, you must be looking for answers of its questions. A coherent system of units is the one which have its derived units made up of from base unit without any other numerical factor other than 1 or some power of ten. During a total solar eclipse the moon almost entirely covers the sphere of the sun. Speed of light = 3 x 108 m/s Hence, they cannot be added or subtracted, so we can say that (a) and (e) are not meaningful. Also, they boost their exam preparation for the annual exam. Q33. ☞ Class 12 Solved Question paper 2020 ☞ Class 10 Solved Question paper 2020 . 664. (b) Angular momentum and Planck’s constant Hence we end up with 3 equations involving 4 unknowns and therefore the values cannot be found. 4. Jan 15, 2021 - MCQ: Units and Measurement - Class 11 Class 11 Notes | EduRev is made by best teachers of Class 11. As the numerical factor is not 1 neither some whole power of ten, it is considered as non-coherent unit. These seven fundamental units are length (l), mass (m), time (t), amount of substance (n), Electric Current (I), Thermodynamic temperature (T) and Luminous intensity (Iv). A unit is defined as a convention to define an amount of physical property in a specific system of units. 5. (a) 663.821 (b) 664 (c) 663.8 (d) 663.82 So the dimensional form of force becomes. J-kg 2. Register online for Physics tuition on Vedantu.com to score more marks in your Examination. This solution provides appropriate answers to the questions provided in the textbook. Q10. We hope the NCERT Solutions for Class 11 Physics Chapter 2 Units and Measurements help you. Consider a quantity ‘A’ with dimensions MLT depending on variables ‘m’, ‘n’, ‘o’ and ‘p’, with dimensions L, M, T and MLT. Dimensional analysis involves checking of a given physical law to check for its validity. Sol: Option (d) is correct because a clock can measure time correctly up to one second. Dimensional equation is the equation used to describe the relation between the fundamental quantity and the derived quantity. Writing energy in dimensional form we get. When expressed in CGS units of dyne/cm2, it will be equal to (1 N = 105 dyne, 1 m2 = 104 cm2) . There are around 3-5 solved test papers in each chapter. Physical Quantities All the quantities in terms of which laws of physics are described, and whose measurement is necessary are called physical quantities. (c)Since 20 mL (1 mL oleic acid + 19 mL alcohol) contains 1 mL of oleic acid, oleic acid in each mL of the solution =1/20 mL. CBSE Worksheets for Class 11 Physics: One of the best teaching strategies employed in most classrooms today is Worksheets. Notes for units and measurements chapter of class 11 physics. Q21. If you have any query regarding NCERT Solutions for Class 11 Physics Chapter 2 Units and Measurements, drop a comment below and we will get back to you at the earliest. Therefore length is expressed in meters/feet, area in square meters/feet and space or volume in cubic meters/feet. Units of Measurement Physics Class 11 Download in pdf Measurement of physical quantities. Need assistance? According to the problem P, Q and R are having different dimensions, since, sum and difference of physical dimensions, are meaningless, i.e., (P – Q) and (R + Q) are not meaningful. (a) 5 (b) 4 (c) 2 (d) 3 Units and Measurements 1.1 Free NCERT Solutions For Class 11 All Subjects; 2 NCERT Solutions for Class 11 Maths. We can thus be able to measure the area over which oleic acid spreads. a highly accurate measuring device will provide measurements very close to the standard, true or known values. In the International System of Units (SI), a solid angle is expressed in a dimensionless unit called a steradian (symbol: sr). The SI unit of gravitational potential is. All the equations that are given above are dimensionally correct i.e. (ii) All other quantities in mechanics can be expressed in terms of length, mass and time. (a) 5.00 mm A zero becomes significant figure if it appears between two non¬zero digits. (a) (P-Q)/R Academic Partner . Any physical law that is valid follows principle of dimensional homogeneity, and hence this analysis is used to check and verify physical laws by expressing them in the form of dimensional equations.It is a useful technique to check the validity of derived relations between physical quantities. Unit and measurement. The number of significant figures in 0.06900 is Multiple Choice Questions. This is a collection of 10 chemistry test questions with answers dealing with unit conversions. Trailing zeros or the zeros placed to the right of the number are significant. These usually result as a product or ratio of physical quantities such that their dimensions get cancelled out leaving a dimensionless entity. Sol: (a) Since Oleic acid does not dissolve in water, hence it is dissolved in alcohol. 1800-212-7858 / 9372462318. Unit and Measurement Multiple Choice Questions(MCQs) & Answers for competitive exams. (a) Linear impulse (c) 2.75 and 2.73 Sol: (a, e) CBSE XI Science Physics Units and Measurement The sun's angular diameter is measured to be 1920'' ( 1920 seconds) . Sol:(a) What is the international system of units? Estimate the ratio of sun-earth diameters. Q29. (c) Year For example, in International System of units we have kilogram for mass, meter for length, seconds/minutes/hours for time, etc. In each mL of solution prepared, volume of oleic acid = 1/20 mL x 1/20 = 1/400 mL. Answer: The accuracy of an instrument is a measure of how close the output reading of the instrument is to the correct value. Class 11 Physics Units and Measurements: Errors in a series of Measurements: Errors in a series of Measurements. One might think that right side may be written as. (b) A stop watch For example consider following equations: ${{\rm{v}}_{\rm{f}}} = {{\rm{v}}_{\rm{i}}} + {\rm{a\: t}}$, ${\rm{L}}{{\rm{T}}^{ - 1}} = {\rm{L}}{{\rm{T}}^{ - 1}} + {\rm{L}}{{\rm{T}}^{ - 2}}{\rm{\: T}}$, ${\rm{L}}{{\rm{T}}^{ - 1}} = {\rm{L}}{{\rm{T}}^{ - 1}} + {\rm{L}}{{\rm{T}}^{ - 1}}$, ${\rm{s}} = {{\rm{v}}_{\rm{i}}}{\rm{\: t}} + \frac{1}{2}{\rm{a\: }}{{\rm{t}}^2}$, ${\rm{L}} = {\rm{L}}{{\rm{T}}^{ - 1}}{\rm{\: T}} + \frac{1}{2}{\rm{L}}{{\rm{T}}^{ - 2}}{{\rm{T}}^2}$, ${\rm{L}} = {\rm{L}} + \frac{1}{2}{\rm{L}}$, $2{\rm{\: a\: s}} = {\rm{v}}_{\rm{f}}^2 - {\rm{v}}_{\rm{i}}^2$, $2{\rm{\: L}}{{\rm{T}}^{ - 2}}{\rm{\: L}} = {\left( {{\rm{L}}{{\rm{T}}^{ - 1}}} \right)^2} - {\left( {{\rm{L}}{{\rm{T}}^{ - 1}}} \right)^2}$, $2{{\rm{L}}^2}{{\rm{T}}^{ - 2}} = {{\rm{L}}^2}{{\rm{T}}^{ - 2}} - {{\rm{L}}^2}{{\rm{T}}^{ - 2}}$. Sol: (b, d) Parsec and light year are those practical units which are used to measure large distances. The physical dimensions are expressed in terms of length, mass and time represented by L, M and T respectively. The SI unit of gravitational potential is. Hence the SI unit of power ‘watt’ is coherent. If P, Q, R are physical quantities, having different dimensions, which of the following combinations can never be a meaningful quantity? All educational material on the website has been prepared by the best teachers having more than 20 years of teaching experience in various schools. Can we say an instrument of high precision is accurate? MCQ quiz on Units and Dimensions multiple choice questions and answers on Units and Dimensions MCQ questions quiz on Units and Dimensions objectives questions with answer test pdf for interview preparations, freshers jobs and competitive exams. Dimensional analysis has following limitations: 1. Dimensional analysis cannot be applied to physical quantities that are associated with exponential or trigonometric functions. Subscribe Now and get such videos daily! Q5. The area of the sheet in appropriate significant figures and error is system the magnitutde of the force is 100 dynes. It has been found that if in mechanics we choose arbitrarily units of any three physical quantities we can express the units of all other physical quantities in mechanics in terms of these. Thus the physical quantities are described in terms of a unit of that quantity. NEET Physics : Units and Measurement. watt. The dimensional formula of force can be found as. Key concept: Principle of Homogeneity of dimensions: It states that in a correct equation, the dimensions of each term added or subtracted must be same. Dimensionless quantities are those physical quantities which do not have any physical dimension associated with them. A stop watch can measure time correctly up to a fraction of a second. (a) (0.25 ± 0.08) m To expresses larger quantities of units in terms of power of tens, certain prefixes are used. NEET Physics Units and Measurement questions & solutions with PDF and difficulty level (d) Lightyear Write the relation between the distances and sizes of the sun and moon. Every correct equation must have same dimensions on both sides of the equation. (b) 5.00 cm Second 5. Physics Notes Class 11 CHAPTER 2 UNITS AND MEASUREMENTS The comparison of any physical quantity with its standard unit is called measurement. Larger the number of significant figures obtained in a measurement, greater is the accuracy of the measurement. Impulse is expressed as. Sol: (b) So the dimensional form of power becomes. What do you mean by the dimensions of a physical quantity? This method is known as dimensional analysis and is used to verify analytical relationship obtained from experimental data. NCERT Exemplar Class 11 Physics Chapter 1 Units and Measurements are part of NCERT Exemplar Class 11 Physics. Knowledge Test! Delete. Q7: What is meant by precision? NCERT Solutions for Class 11 Physical Education will provide you all topics of CBSE class 11 Physical Education syllabus we will explain all the solution in detail so that it can help to improve your knowledge conceptually and you will understand the subject and fall in love with Physical Education. The number of significant figures in 0.06900 is […] These solutions are also so helpful for students who are preparing for competitive entrance exams like JEE and NEET . Show that the following pairs of physical quantities have identical dimension (i) momentum and impulse (ii) torque and energy and (iii) energy and work. ISC Specimen Papers 2020 for Class 11; ICSE Time Table 2020 Class 10; ISC Time Table 2020 Class 12; Maths; A Plus Topper. If a physical quantity is dependent on more than 3 variables than we cannot find the relation between them. Basic or fundamental units are those seven units which are called as independent units. CBSE Class 11 Physics Worksheet for students has been used by teachers & students to develop logical, lingual, analytical, and problem-solving capabilities. Although we cannot find the values of dimensionless constants but we can find out the relations between physical quantities. These solutions for Units And Measurements are extremely popular among Class 11 Science students for Physics Units And Measurements Solutions come handy for quickly completing your homework and preparing for exams. If the digit to be dropped is 5 followed by digits other than zero, then the preceding digit is raised by one. NEET Physics : Units and Measurement. 4. ‘L’. ...kg m–3. Solved Examples on Unit and Dimensions Problem 1:-The speed of sound v in a gas might plausibly depend on the pressure p, the density ρ, and the volume V of the gas. (c) A digital watch Q42. The principle of homogeneity of dimensions is used to verify the physical laws involving physical quantities. Given reason for your answer. Question 1. (c) Mars has approximately half of the earth’s diameter. Sol: According to the problem, distance of the galaxy = 1025m. On the other side, derived units can be defined as the dependent units resulting in the ratio or product of the fundamental units. 3. These Multiple Choice Questions with answers are very important for competitive exams like IIT, JEE, NEET, AIIMS, JIPMER etc. Let us first check the units. Class 11 Physics NCERT Solutions Chapter wise. Instead it spreads on the water surface pushing the lycopodium powder away to clear a circular area where the drop falls. If velocity of light c, Planck’s constant h and gravitational constant G are taken as fundamental quantities, then express mass, length and time in terms of dimensions of these quantities. When it is closest to the earth it is at about 1/2 AU from the earth. Which of the following time measuring devices is most precise? For example, let’s derive an expression for kinetic energy just with the knowledge that it depends upon the mass and velocity of a body. Hence, (c) is not the correct option. 4. (b) Universal gravitational constant (G) Q3. Without a unit a physical property cannot be distinguished or described. And area can be expressed as ${{\rm{L}}^2}$ so, ${\rm{P}} = \frac{{{\rm{ML}}{{\rm{T}}^{ - 2}}}}{{{{\rm{L}}^2}}}$, ${\rm{P}} = {\rm{M}}{{\rm{L}}^{ - 1}}{{\rm{T}}^{ - 2}}$. All non-zero digits are significant. So an atomic clock can measure time most precisely as precision of this clock is about 1 s in 1013 s. Q27. If Planck’s constant (h) and speed of light in vacuum (c) are taken as two fundamental quantities, which one of the following can, in addition, be taken to express length, mass and time in terms of the three chosen fundamental quantities? Some of the derived physical quantities are velocity, acceleration, momentum, force, pressure, etc. All questions and answers from the NCERT Book of Class 11 Science Physics Chapter 2 are provided here for you for free. If digit to be dropped is 5 or 5 followed by zeros, then preceding digit is left unchanged, if it is even. Suppose mass is the unit, then we can conclude that weight of the lion is 200 times to that of a goat. Physical Quantities All the quantities in terms of which laws of physics are described, and whose measurement is … Now consider 2.737, here also the digit to be dropped is 5, then the preceding digit is raised by one, if it is odd. Are you sure? Express unified atomic mass unit in kg. Hence it is proved that the torque and energy have same dimensional forms. 4. J. J-kg-1. Sol: Normally each physical quantity requires a unit or standard for its specification, so it appears that there must be as many units as there are physical quantities. Name the device used for measuring the mass of atoms and molecules. Derived units are composed of the fundamental units and are originated from the products and ratios of the fundamental units. HSSLive Plus Two; HSSLive Plus One; Kerala SSLC; Exams; NCERT Solutions for Class 10 Maths; NIOS; Chemistry; Physics; ICSE Books; Plus One Physics Chapter Wise Previous Questions Chapter 2 Units and Measurement. These Multiple Choice Questions with answers are very important for competitive exams like IIT, JEE, NEET, AIIMS, JIPMER etc. In an experiment to estimate ‘the size of a molecule of oleic acid, 1 mL of oleic acid is dissolved in 19 mL of alcohol. Key concept: Significant figures in the measured value of a physical quantity tell the number of digits in which we have confidence. Now, 1 drop of this diluted solution is placed on water in a shallow trough. This solution provides appropriate answers to the questions provided in the textbook. Those are spatial dimensions and are represented in terms of Length i.e. (c) Energy/Area Here the digit to be dropped is 5, then preceding digit is left unchanged, if it is even. Let us round off 2.745 to 3 significant figures. (c) a constant which has a unit Multiple Choice Questions (MCQ) for Units and Measurement - CBSE Class 11-science Physics on Topperlearning. The SI unit for momentum is kgms-1 or N-s Momentum can be written as. CBSE Class 11 Physics Chapter-wise Question papers. Torque causes the body to rotate. At the nuclear level, the magnitudes of energy are very small. Therefore, the MKS system was promoted to be called as The International System of Units abbreviated as the SI system. Download latest questions with answers for Physics Units and Measurements in pdf free or read online in online reader free. J-kg. t1 = 39.6 s, t2 = 39.9 s and t3 = 39.5 s There are units defined for every physical quantity and that physical quantity is expressed in terms of that specific unit. Short Answer Type Questions If the digit to be dropped is less than 5, then the preceding digit is left unchanged. Q1: Light year is a unit of (a) time (b) distance (c) sunlight intensity J-kg. 2. CBSE papers with answers and solutions for chapter 2 Units and Measurements class 11th Physics includes practice question papers with 10-12 questions in each test paper. UNITS AND MEASUREMENT 17 (a) (b) Fig. (d) Angular momentum, Q16. Since it is proved that the momentum (p) and impulse (J) have same dimensions. Q11. For JEE Main other Engineering Entrance Exam Preparation, JEE Main Physics Units, Dimensions and Errors Previous Year Questions with Solutions is given below. A unit is defined as a convention to define an amount of physical property in a specific system of units. 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