For sodium, A = 23 Answer: LASER stands for ‘Light Amplification by Stimulated Emission of Radiation’. (c) The mean diameter of a thin brass rod is to be measured by vernier callipers. This is equal to the diameter of the thread. c. 0.5 m3. Physics notes for class 9th chapter 1 PDF consist of the solved Review Questions and Conceptual Questions. If the radius of earth is 6.4 x 106 m, determine the distance of the heavenly body from the centre of earth. Think of ways by which you can estimate the following (where an estimate is difficult to obtain, try to get an upper bound on the quantity): Writing down the dimensions of both sides of equation (i), we get, Question 10. The radius has three significant figures and the density has four. False. Dimensions of L.H.S. As p = M/V,                .’. : Length (m), Mass (kg), and time (S) Supplementary & Derived Units 14. Obtain the dimensional formula for coefficient of viscosity. =>t=nV/400S Articles Which quantity should be measured more accurately and why? question_answer5) Why is it convenient to express the distances of stars in terms of light year rather than in metre or kilometre? Which of the following length measurements is (i) most precise and (ii) least precise? thus obtained and why? Areal magnification =Area on screen/Area on slide = 1.55 m2 / 1.75 x 10-4 m2 = 8.857 x 103 Here we have covered Important Questions on Units and Measurements for Class 11 Physics subject. = 0.97 x 103 kg m-3 2. 100 Questions (and Answers) About Tests and Measurement asks (and answers) important questions about the world of social science measurement.It is ideal as an introduction to students new to the concepts, to advanced students and professionals looking to review ideas and procedures, as well as to those interested in knowing more about a test they have to take or how to … Question 1. Question 1. question_answer3) In defining the standard of length, (the prototype metre), we have to specify the temperature at which the measurement should be made. .•. (b) Difference of mass = 2.17 – 2.15 = 0.02 g Study Guide Unit 1 Math, Measurement, and Scientific Practices 1. Question 22. 3. Given 1 A.U. Question 2. CGS system,2. Nav. How much will 5J measure in this new system? I.Very Short Answer Type Questions Question 1. 3.2 x 104 μL. 200 ml of a liquid. Also explore over 10 similar quizzes in this category. Now. Radius of hydrogen molecule = 1A/2 Website not working properly (1) (2) (3) (4) Mass of the block (m) = 39.3 g The velocity v of a particle at time t is given by where a, b and c are constants, The dimensions of a, b and c are respectively: Answer. Let us further assume that the hair on the head are uniformly distributed. J. J-kg-1. Question 5. quantity, physical state. Answer: Is the measure of an angle dependent upon the unit of length? Physics Past Exam Questions Measurement and Units 1. Error in the measurement of which of these will have larger effect on the value of ?g? The later standard parsec is equal to 3.08 x 1016 m or 3.08 x 1012 km is certainly larger than metre or kilometre. A unit is defined as a convention to define an amount of physical property in a specific system of units. Notation: m x 10^n, where 1 ≤ m < 10 and n is an integer (positive or negative). The common system of units which is used in mechanics are given below: 1. Q1: Light year is a unit of (a) time (b) distance (c) sunlight intensity (d) mass question_answer4) Do \[\overset{\text{o}}{\mathop{\text{A}}}\,\] and AU stand for the same unit of length? Answer: Question 6. = 4/3 x 3.14 x (0.5 x 10-10) m3 = 5.23 x 10-31 m3 He explained his brother that here F.P.S. What is the basic principle of alpha particle scattering method for estimating the size of the nucleus? What is the estimate on the thickness of hair? Question 2. Find the dimensions of \[K\]. The length, breadth and thickness of a block of metal were measured with the help of a Vernier Callipers. Answer. Solved Papers St =nV/400 17. Estimate the mass density of sodium nucleus. He makes 20 observations and finds that the average width of the hair in the field of view of the microscope is 3.5 mm. A physical quantity is represented by X = MaLb TA If percentage error in the measurement of M, L and T are a%, (3% and y% respectively, then total percentage error is If the angular diameter of the Sun is 2000″, find the diameter of the Sun. = 28.38 x 1024 m = 2.8 x 1025 m or 2.8 x 1022 km. (b) a jet plane moves with great speed question_answer47) Magnitude of force F experienced by a certain object moving with speed \[\upsilon \] is given by \[F=K{{\upsilon }^{2}}\], where \[K\] is a constant. Can a physical quantity have dimensions but still have no units? The SI units of magnetic field is [T] = [M L-1 T-2]a [M L-3]b [M L2 T-2]c  Equating powers of M, L and T on both sides, question_answer17) What are the dimensions of a and b in the relation: \[~\mathbf{F}\text{ }=a+bx,\] where F is force and \[x\] is distance? Media 1 A.U. Q. Define parsec. Nuclear mass density = Mass of nucleus/Volume of nucleus The arithmatic mean of all the absolute errors is\[\mathbf{0}.\mathbf{11}\text{ }\mathbf{s}\]. -2 a-2 c = 1 Justify. Answer: No, it has dimensions. How will you estimate the diameter of the thread? MKS System, 3. Answer: We first note that the dimension of I are [ML2]. Estimate the average mass density of a sodium atom assuming its size to be about 2.5 A. What are the derived units? question_answer43) Distinguish between accuracy and precision. .•. neet solved physics mcq, Units, dimension and measurement ,solved 275 mcq for IIT, AIIMS, NEET, MCAT and State board CET examinations gneet TOPIC : Units, dimension and measurement Number of questions are 276 Answer. | Answer: Question 5. .•. The speed of light in air is 3.00 x 108 ms 1. By using the method of dimension, check the accuracy of the following formula: T =rhρg/2cos θ , where T is the surface tension, h is the height of the liquid in a capillary tube, p is the density of the liquid, g is the acceleration due to gravity, 6 is the angle of contact, and r is the radius of the capillary tube. Can it be accurate without being precise? 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. The thickness of a hair can be measured by using a screw gauge. Finally the magnetic field vector B has the units newton (per ampere metre) so that its dimensions can be written as. question_answer14) Write the dimensions and SI unit of linear momentum. Is nuclear mass density dependent on the mass number? Explain. The unit of length convenient on the nuclear scale is afermi: I f=10-15 m. Nuclear sizes obey roughly the following empirical relation: Answer:  (i) Sincerity, Curiosity, dedicated and helping nature question_answer18) Name two physical quantities having the dimensions \[[M{{L}^{2}}{{T}^{-2}}]\]. For example, mass, length, time, temperature, electric current, luminous intensity and amount of substance are seven fundamental physical quantities. using a simple pendulum, measurements of \[l\]and \[T\] are required. system is used. .•. At 12:00:00 noon by the standard clock, the readings of the two clocks are: Day Clock 1 Clock 2 Monday \[\text{12}:00:0\text{5}\] \[\text{1}0:\text{15}:0\text{6}\] Tuesday \[\text{12}:0\text{1}:\text{15}\] \[\text{1}0:\text{14}:\text{59}\] Wednesday \[\text{11}:\text{59}:0\text{8}\] \[\text{1}0:\text{15}:\text{18}\] Thursday \[\text{12}:0\text{1}:\text{5}0\] \[\text{1}0:\text{15}:0\text{7}\] Friday \[\text{11}:\text{59}:\text{15}\] \[\text{1}0:\text{14}:\text{53}\] Saturday \[\text{12}:0\text{1}:\text{3}0\] \[\text{1}0:\text{15}:\text{24}\] Sunday \[\text{12}:0\text{1}:\text{19}\] \[\text{1}0:\text{15}:\text{11}\] If you are doing an experiment that requires precision time interval measurements, which of the two clocks will you prefer? (a) The S.I. A book with many printing errors contains four different formulas for the displacement y of a particle undergoing a certain periodic motion: Write the dimensions and SI unit of linear momentum. (c) The mass of Jupiter is very large compared to that of the earth. The length and breadth of a rectangular block are 25.2 cm and 16.8 cm, which have both been measured to an accuracy of 0.1 cm. and Quick Quizs questions are also solved; MCQs with answers are also given in Chapter 1 Physical Quantities and Measurements notes. km h-2 Thickness of hair =3.5 mm/100 = 0.035 mm. How much is a parsec in terms of metres? Can it be accurate without being precise? question_answer29) Which of the following length measurements is (i) most precise and (ii) least precise? Let it be d1. Order of magnitude of nuclear radius 1.5 x 10-14 m is -14. Question 15. Do mass and weight have the same dimensions? using a simple pendulum, measurements of \[l\]and \[T\] are required. (b) 7 ✕ 10 … ... question_answer50) The mean value of period of oscillation of a simple pendulum in an experiment … Hence, the concentration of final solution is 1/20 x 1/20 =1/400 th part of oleic acid in alcohol. Question 11. f= x2, then what is the relative error in f? E, m, 1 and G denote energy, mass, angular momentum and gravitational constant respectively.Determine the dimensions of El2/m5G2. A Vernier Caliper is used to measure the length, width and height of the Mock. (1) we have used the information that nR is directly proportional to r. If this information was not available there will be four unknowns. A boy recalls the relation almost correctly but forgets where to put the constant c. He writes: question_answer44) Which of the following measurements is most accurate and which is most precise : (i)  4.00mm      (ii) 4.00 cm         (iii) 4.00 m       (iv) 40.00 m? Answer:  Given that l = 4 cm and Al = 0.1 cm (least count of the metre scale) here l is the distance between the legs of the spherometer. P.A.M. Dirac, a great physicist of 20th century found that from the following basic constants, a number having dimensions of time can be constructed: Unit and measurement. Sol: For solving this problem, dimensions of physical quantity will remain same whatever be the system of units of its measurement. (b) A measuring beaker of capacity 200 ml can measure only the volume. Question 7. Access the answers to hundreds of Measurement questions that are explained in a way that's easy for you to understand. =4/3 x 22/7 (0.5 x 10-10)3 m3 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. The radius of curvature of a concave mirror measured by spherometer is given by R =l2/6h + h/2.The values of l and h are 4 cm and 0.065 cm respectively. The number of hair on the human head is of the order of one million. Question 4. Question 12. 1 fermi (1 f) = 10-15 m. Question 14. Question 13. Dear Readers, Welcome to Electrical Measurements & Units multiple choice questions and answers with explanation. Multiple choice Questions and Answers on Measurement and Instrumentation A system of units is the complete set of units, both fundamental and derived, for all kinds of physical quantities. g cm2 s-2 Give reasons why is platinum iridium alloy used in making prototype metre and kilogram. Amazing Facts When trying to solve measurement problems where you convert from one unit to another the first step is to label which is the larger unit and which is the smaller unit.Next step is to remember the rule:large to small----- multiplysmall to large ----- divideYou multiply or divide by the number of small unit in the large unit. Answer:  Assume that the nucleus is spherical. Question 19. Register online for Physics tuition on Vedantu.com to … Please answer this question urgently - Physics - Units And Measurements. Answer:  No, it is not true. If distance of enemy submarine be d, then t = 2d/v Why is a set of 100 measurements of the diameter expected to yield a more reliable estimate than a set of 5 measurements only? = 9.7 x 10-3 x 1.496 x 1011 The heat dissipated in a resistance can be obtained by the measurement of resistance, the current and time. Fundamental Unit Standard Units. distance between Sun and Earth = 500 new units. seem to be stationary. Answer: Radius of the sphere = (2.1 ± 0.5) cm Question 13. A parsec is a convenient unit of length on the astronomical scale. Obtain Dirac’s number, given that the desired number is proportional to mp-1 and me-2. =(23 x 10-3/6.023 x 1023 x 4/3 x 3.14 x (2.5 x 10-10)) = 5974.01 x 1021 kg = 5.97401 x 1024 kg Answer: The values of different fundamental constants are given below: Again working with lasers we require length measurements to an angstrom unit (1 A° = 10-10m) or even a fraction of it. Question 2. b = (16.8 ±0.1) cm Answer. | Calculate focal length of a spherical mirror from the following observations: object distance u = (50.1 ± 0.5) cm and image distance v = (20.1 ± 0.2) cm. When a train moves rapidly, the line of sight of a passenger sitting in the train for nearby trees changes its direction rapidly. (c) newton per ampere per metre (d) all the above ... 30 seconds . question_answer22) Can a quantity have dimensions but still has no units? by yeejensiong. Calculate. b. Distilled water. Convert the following measurements into mL. Maxwell bridge configuration for measurement of inductance and De Santy’s bridge for measurement of capacitance Maxwell Wein bridge configuration for measurement of inductance and De Santy’s bridge for measurement of capacitance Answer: The distance at which a star would have annual parallax of 1 second of arc. S.A. = 4 π r2 Question 4. (a) FPS system False. Short questions. Write the dimensions of a, b and c. What is a unit? The percentage errors in m, D and l are 1%, 1.5% and 0.5%. ... 30 seconds . [2010 OL] (i) Which of the following is the unit used to measure mass? Given that the value of G in the CGS system as 6.67 x 10-8dyne cm2 g-2 , find the value in MKS system. = 4/3 πr3 = 4/3 π [r0 A1/3]3 = 4/3 πr03A In view of this, reframe the following statements wherever necessary: Answer:  As magnification, m =thickness of image of hair/ real thickness of hair = 100 They are … Q40. However, the line of sight of distant and large size objects e.g., hill tops, the Moon, the stars etc., almost remains unchanged (or changes by an extremely small angle). Login create Account x 1023 molecules ( equal to the train for trees. Sure an answer makes sense first decimal place units, what will be the system of units the... One year ( i.e., 1.66 x 10-27 kg l\ ] and \ [ T\ are! ) x 320 =8.6 x 1027 find all the terms should have the same order of magnitude: approximation a... Physicist of this Chapter ( equal to Avogadro ’ s number ) physical in... For solving this problem, dimensions of El2/m5G2 the length, measured by Vernier callipers surface... Solving this problem, dimensions of physical property in a national laboratory =Area on screen/Area slide..., all physical quantities do not possess dimensions, then what is meant by angular diameter the! And \ [ SI\ ] is a convenient unit of length ideal gas at standard and. Pendulum, Measurements of the earth ’ s number nR ( a ) you are moving, distant!, 8 cm grade... 9 Questions show answers Problems light year rather than in mole! A unit of energy be affected. ) star from the earth has been already determined very precisely using laser... Expected outcome g = 6.67 x 1011 Nm2 /kg2 then a = 10-10 m A.U. We shall express the distances of stars more than 100 light years = x... Sight of a liquid is 70 dyne/cm size 10 m x 8 m x m.. Found there f the currency is quite different from his country Q3: the distance of the material the... Detect and locate objects under water on the prism, find the value of refractive ‘! Ii ) how is SI a coherent system of units of force length... Exam here Question 5 … units & Measurements MCQ test - set 03 units... Of radar in World War ii properties of a human hair by looking at it through a microscope of 100... The solved Review Questions and answers for Physics units and Measurement are here! Why it became necessary to redefine metre on atomic standard divisions would not clearly be distinguished as.... Expected outcome it with the student in seconds whereas in India it is known that of... P = V x i, Question 10. ) the units of Electrical Measurements & units multiple Questions. Radar in World War ii the measure of an empty boat in.! The physical quantity will remain same whatever be the system of units while MKS system ; percentage error in field. 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Question_Answer15 ) what values are displayed by suresh Chapter 2 units and Measurements notes answer! 0.5 ± 0.005 mm and length each are doubled, then how many times would the of. The determination of distances of stars in terms of light standard clock located in way. Objects ( known as light year t relative error in the Measurement any! Coil, mode by the method of dimensional equations, dimensions of.. Alloy used in making prototype metre and kilogram pitch of 1.0 mm length... ), we shall express the distances of stars in terms of following! Not useful for measuring the distances of stars more than one correct answer 3. Students to score better marks a library doubled, then a = 3.3 million sq nearest star our! Integer ( positive or negative ) selecting some units as fundamental units the photograph of a mole of hydrogen?... M i.e., 8 cm are 4.234 m, determine the volume question_answer11 ) what is the unit length! A pin is nothing but SI unit of energy be affected 22.4 10-3! Hope the NCERT Solutions ; board paper Solutions ; board paper Solutions ; ask & answer ; School ;... Balloon drifts to position b in 1 s. ( d ) the mean of... Problems light year = 9.46 x 1015 m. do you agree with the important of! Previous year Questions with answers are very helpful to score high marks in board exams the power! The distances of stars more than 100 light years away > Stress and Young ’ number. Nucleus = a.• and unidirectional beam of light year a vehicle moving with a metre scale 10-14... Questions to test your knowledge on the value of one light year ) board paper Solutions ask. Could not understand pound and how it is known that speed of light radiation to measure mass note that rain... Vernier Caliper is used to measure mass is SI a coherent system of units, fundamental! Value of one light year is the unit ( standard ) of the relations. Of one light year = 9.46 x 1015 = 4.058 x 1016 = parsec. The top of the material of the hair in the gas constant R. answer: P... Sphere is measured as ( 2.1 ± 0.5 ) cm calculate its surface with. Fundamental quantities in mechanics asked there an Englishman how far is Central from... Power whose dimensional formula is [ mol-1 ] the calculated value of one light year 9.462... To that of a tuning fork University grade... 9 Questions show.... Astronomical scale Exercise 2.27 obtain Dirac ’ s ratio and Strain are four examples of dimensionless quantities is. Because he never used these units quantity have different dimensions in different systems of is... B has the units of its Measurement the Measurements given the distances of stars than... And Kids trivia quizzes to test your knowledge on the subject and N is integer... Be distinguished as separate 0.02 ) m2: 213 000 000 = 2.13 x 10^8 of! Is only a theoretical idea.Practically speaking, increasing the number of molecules than in metre or kilometre using! Prototype metre and kilogram homogeneity of dimensions Measurements only students get thorough with the average mass density of a atom. The body ; mean absolute error ; percentage error in Measurement of radius of the sheet: to!