Find the dimensions of \[K\]. If A be the base area of the boat, then volume of water displaced by boat, V1 = Ad2 = 5974.01 x 1021 kg = 5.97401 x 1024 kg (a) pressure (b) force Answer: Question 4. Units and Measurements's Previous Year Questions with solutions of Physics from JEE Main subject wise and chapter wise with solutions. Jobs Answer: Question 3. What is it called? Hence more reliable result can be obtained. Q3: The surface tension of a liquid is 70 dyne/cm. Register online for Physics tuition on Vedantu.com to … Suresh went to London to his elder brother Lalit who is a Civil Engineer there. The SI units of the universal gravitational constant G are Question 2. Question 6. Why is this ratio so large? Answer:  No, it is not true. Answer: 6.67 x 10-8 dyne cm2 g-2 = 6.67 x 1011 Nm2 /kg2 . A parsec is a convenient unit of length on the astronomical scale. Let us further assume that the hair on the head are uniformly distributed. Answer:  (a) Wrap the thread a number of times on a round pencil so as to form a coil having its turns touching each other closely. = 1920 x 4.85 x 10-6 x 3.8452 x 108 m = 35806.5024 x 102 m = 3581 x 103 m 3581 km. Suggest an indirect method for measuring the height of a tree on a sunny day. (a) kg m2 s-2 (b) kg-1 m3 s-2 (c) N kg2 m-2 (d) N kg2 m-2 J. J-kg-1. 30. Answer: It is given that radius of sodium atom, R = 2.5 A = 2.5 x 10-10 m Explain this statement clearly: = 4/3 x 3.142 x (6.37 x 106)3m3 question_answer10) Why is parallax method not useful for measuring the distances of stars more than 100 light years away? Articles Practice the multiple choice questions to test understanding of important topics in the chapters. .•. get Question 21. Long Answer Type Questions. (B) Hygrometer. of divisions on circular scale = 1 x 10-3/100 = 1 x 10-5 m If instead of mass, length and time as fundamental quantities, we choose velocity, acceleration and force as fundamental quantities and express their dimensions by V, A and F respectively, show that the dimensions of Young’s modulus can be expressed as [FA2 V-4]. Chapter – 1. John studies for 3 hours, then “3” is the quantity and “hour” is the unit of time 1. Answer: Question 2. A famous relation in physics relates ‘moving mass’ m to the ‘rest mass’ m0 of a particle in terms of its speed v and the speed of light c. (This relation first arose as a consequence of special relativity due to Albert Einstein). Obtain the dimensions of relative density. 27. Diameter of Jupiter D = θ x d = 1.73 x 10-4 x 824.7 x 109 m where k is a dimensionless constant of proportionality. Professionals, Teachers, Students and Kids Trivia Quizzes to test your knowledge on the subject. What are the five steps of the scientific method (in order) and an explanation of each? Answer:  Extremely precise measurements are needed in modem science. Question 7. Question 24. Answer: (a) The average rainfall of nearly 100 cm or 1 m is recorded by meteorologists, during Monsoon, in India. Free Question Bank for 11th Class Physics Physical World Units and Measurements Conceptual Problems The two specific heat capacities of a gas are measured as Cp = (12.28 ± 0.2) units and Cv = (3.97 ± 0.3) units. The maximum percentage error in the measurement of its density is = area x height x density = 3.3 x 1012 x 1 x 1000 kg = 3.3 x 1015 kg. Calculate the percentage error in the calculated value of density. Answer: 1 micron (1 p) = 10-6 m CBSE Papers, Questions, Answers, MCQ ... Blog provides NCERT solutions, CBSE, NTSE, Olympiad study material, ... CBSE Class 11 - Physics - Units and Measurements - MCQs Multiple Choice Questions . (c) the mass of Jupiter is very large 4.29 light years = 4.29 x 9.46 x 1015 = 4.058 x 1016 m The nearest divisions would not clearly be distinguished as separate. From the table of fundamental constants in this book, try to see if you too can construct this number (or any other interesting number you can think of). The percentage errors in m, D and l are 1%, 1.5% and 0.5%. Long Answer Type Questions. Question 2. Answer: Volume of one hydrogen atom = 4/3 πr3 (volume of sphere) (a = maximum displacement of the particle, v = speed of the particle, T = time-period of motion)Rule out the wrong formulas on dimensional grounds. A system of units is the complete set of units, both fundamental and derived, for all kinds of physical quantities. Question 1. NCERT Solutions for Class 11 Physics Chapter 2 Units and Measurements are part of Class 11 Physics NCERT Solutions. If distance of Venus be d, then t = 2d/c Give reason (i) \[l\mathbf{ =5cm}\] (ii) \[l\mathbf{=5}\mathbf{.00cm}\] (iii) \[\mathbf{5}.\mathbf{000}\text{ }\mathbf{cm}\] (iv) \[\mathbf{5}.\mathbf{000}\text{ }\mathbf{cm}\] (\[\upsilon \])\[~\mathbf{5}.\mathbf{00000}\text{ }\mathbf{cm}\]. A Vernier Caliper is used to measure the length, width and height of the Mock. Answer:  Assume that the nucleus is spherical. 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. A laser light beam sent to the moon takes 2.56 s to return after reflection at the Moon’s surface. Reynold’s number NR (a dimensionless quantity) determines the condition of laminar flow of a viscous liquid through a pipe. 3.2 x 104 μL. From dimensional considerations, find a possible relation for the frequency of a tuning fork. = 22.4 litre = 22.4 x 10-3 m3 Now. This is 0.19 cm3 lower than the nominal measured value. | So, the nuclear mass density is nearly 50 million times more than the atomic mass density for a sodium atom. question_answer32) Which of the following measurements is more accurate and why? Unit and measurement. 10. Question 4. where n1 and n2 are number of particles per unit volume for the value of x1 and x2 What do you understand by fundamental physical quantities? (ii) Which of the following is the unit used to measure time? .-. There are several systems of units with different conventions to express these units. Question 2. Volume of one mole of hydrogen, VH Answer. So, the unit of c is ms-2. thickness (f) = 0.37 cm 2. By practising these questions, students get thorough with the important topics of this chapter. How much is this distance in terms of parsecs? It is on account of the fact that in solid phase atoms are tightly packed and so the atomic mass density is close to the mass density of solid. a=0,b=+(1/2) and c=+(1/2). Answer: The measured (nominal) volume of the block is, Question 8. 2. Knowledge Test! question_answer5) Why is it convenient to express the distances of stars in terms of light year rather than in metre or kilometre? The first system, in which unit of power is 1 watt, is SI system in which M1 = 1 kg,L1 = 1 m and T1= ls in second system, M2 = 100 g, L2 = 20 cm and T2 = 1 min = 60 s. Question 24. 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): NCERT Solutions Class 11 Business Studies, NCERT Solutions Class 11 Entrepreneurship, NCERT Solutions Class 11 Indian Economic Development, NCERT Solutions Class 11 Computer Science, Chapter 7 System of particles and Rotational Motion, Chapter 9 Mechanical Properties Of Solids, Chapter 10 Mechanical Properties Of Fluids, NCERT Solutions for Class 10 Science Chapter 1, NCERT Solutions for Class 10 Science Chapter 2, Periodic Classification of Elements Class 10, NCERT Solutions for Class 10 Science Chapter 7, NCERT Solutions for Class 10 Science Chapter 8, NCERT Solutions for Class 10 Science Chapter 9, NCERT Solutions for Class 10 Science Chapter 10, NCERT Solutions for Class 10 Science Chapter 11, NCERT Solutions for Class 10 Science Chapter 12, NCERT Solutions for Class 10 Science Chapter 13, NCERT Solutions for Class 10 Science Chapter 14, NCERT Solutions for Class 10 Science Chapter 15, NCERT Solutions for Class 10 Science Chapter 16, CBSE Previous Year Question Papers Class 12, CBSE Previous Year Question Papers Class 10, Accuracy, precision of instruments and errors in measurement, Dimensional formulae and dimensional equations, Dimensional analysis and its applications. (cm)3 s-2 g-1. (c) Least count of optical instrument = 6000 A (average wavelength of visible light as 6000 A) = 6 x 10-7m As the least count of optical instrument is least, it is the most precise device out of three instruments given to us. i. e., [L1 T-1] = dimensionless, which is incorrect. 1. Name two pairs of physical quantities whose dimensions are same. For example, to ascertain the speed of an aircraft, one must have an accurate method to find its positions at closely separated instants of time. By practising these questions, students get thorough with the important topics of this chapter. (b) a screw gauge of pitch 1 mm and 100 divisions on the circular scale. Check if your guess is correct from the following data: mass of the Sun = 2.0 x 1030 kg, radius of the Sun = 7.0 x 108 m. (d) The relative density of lead is 11.3. Answer: RADAR stands for ‘Radio detection and ranging’. (In fact, since you are aware that you are moving, these distant objects seem to move with you). Convert the following measurements into mL. Try this amazing Units And Measurements! (a) \[\mathbf{0}\mathbf{.0002 g}\] (b) \[\mathbf{20}\mathbf{.0 g}\]. MKS System, 3. =11.3 x 103 kg m-3 [1 kg =103 g,1m=102 cm] To measure any quantity or compare two quantities we need an internationally acquired standard called Unit. If the maximum error in the measurement of these quantities is 1 %, 2 % and 1 % respectively, what is the maximum error in determination of the dissipated heat? It is known that the refractive index ‘μ’ of the material of the prism is given by Also, wherever you can, give a quantitative idea of the precision needed. Volume of one mole atom of sodium, V = NA .4/3 π R3 Check by the method of dimensional analysis whether the following relations are correct. (a) the total mass of rain-bearing clouds over India during the Monsoon (a) a vernier callipers with 20 divisions on the sliding scale. 31. =11.3 x 103 kg m-4. In fact its dimensional formula is [mol-1]. question_answer38) Suggest a distance corresponding to each of the following order of length: (i) \[{{10}^{7}}\mathbf{m}\] (ii) \[\mathbf{1}{{\mathbf{0}}^{\mathbf{4}}}\mathbf{m}\] (Hi) \[{{10}^{2}}\mathbf{m}\] (iv) \[\mathbf{1}{{\mathbf{0}}^{\mathbf{-}}}^{\mathbf{3}}\mathbf{m}\] (v) \[\mathbf{1}{{\mathbf{0}}^{\mathbf{-6}}}\mathbf{m}\] (vi) \[\mathbf{1}{{\mathbf{0}}^{\mathbf{-14}}}\mathbf{m}\]. What is its value? question_answer29) Which of the following length measurements is (i) most precise and (ii) least precise? Question 2. Hence, mass of the earth = 5.97 x 1024  kg. Also explore over 10 similar quizzes in this category. Answer: (i) Work (ii) Torque (iii) Moment of force (iv) Couple (v) Potential energy (vi) Kinetic energy. True. False. = 7.4 x 1010 m. Question 4. All Chapter 2 - Units and Measurement Exercises Questions with Solutions to help you to revise complete Syllabus and … A laser signal is beamed towards the planet Venus from Earth and its echo is received 8.2 minutes later. Units & Measurements MCQ Test - Set 03 GK Units Edit G.K. Question 2. Find the Earth’s average density to appropriate significant figures. (a) 1 kg m2 s-2 = …. Hence, we shall express the value of P after rounding it off as P = 3.8. (a) 70 N/m. Answer: Given angular diameter θ = 35.72= 35.72 x 4.85 x 10-6 rad | (B) Speed of light. 2. Mass of the block (m) = 39.3 g d = 1/2ct = 1/2 x 3 x 108 x 8.2 x 60 m by yeejensiong. (a) FPS system Two clocks are being tested against a standard clock located in a national laboratory. = 7.38 x 1010 m Multiple Choice Questions done Units and Measurements Conceptual Problems Total Question - 50 question_answer1) What is the necessity of selecting some units as fundamental units? Answer: Let the distance covered is S, State the number of significant figures in the following: What is it called? Notes What do you mean by order of magnitude? Question 3. Observation/question- what we see which leads us to the question we want to answer Hypothesis- A testable statement about the expected outcome. If the length and time period of an oscillating pendulum have errors of 1% and 2% respectively, what is the error in the estimate of g? Accuracy of 1 part in 1011 to 1012. 1 nano metre (1 nm) = 10-9 m Assume that the human head is a circle of radius 0.08 m i.e., 8 cm. Here you can get Class 11 Important Questions Physics based on NCERT Text book for Class XI. .•. (e) We can determine the volume of the class-room by measuring its length, breadth and height. IV. Then redissolve 1 mL of this solution in 20 mL of alcohol. I.Very Short Answer Type Questions Question 1. 200 ml of a liquid. .•. Study Guide Unit 1 Math, Measurement, and Scientific Practices 1. answer choices . Comment on the statement: "To define a physical quantity for which no method of measurement is given or known has no meaning.". Question Answer. 15. In what range do you expect the mass density of the Sun to be, in the range of densities of solids and liquids or gases? Answer: Here area of the house on slide = 1.75 cm2 = 1.75 x 10-4 m2 and area of the house of projector-screen = 1.55 m2 What is the significance of this number? [2007 OL] Knowledge Test! If the radius of earth is 6.4 x 106 m, determine the distance of the heavenly body from the centre of earth. v/u= tan θ, where u is velocity of rain. question_answer3) In defining the standard of length, (the prototype metre), we have to specify the temperature at which the measurement should be made. The mean value of the body; Mean absolute error; Percentage error; Answer: 1. A force of (2500 ±5) N is applied over an area of (0.32 ± 0.02) m2. Find the dimensions of \[K\]. Give reason (i) \[l\mathbf{ =5cm}\] (ii) \[l\mathbf{=5}\mathbf{.00cm}\] (iii) \[\mathbf{5}.\mathbf{000}\text{ }\mathbf{cm}\] (iv) \[\mathbf{5}.\mathbf{000}\text{ }\mathbf{cm}\] (\[\upsilon \])\[~\mathbf{5}.\mathbf{00000}\text{ }\mathbf{cm}\]. Question 2.7. Find the Young’s modulus of the material of the wire from this data. What does SONAR stand for? Why is parallax method not useful for measuring the distances of stars more than 100 light years away? 17. Therefore, the inter-stellar or intergalactic distances are certainly larger than the distances between two cities on earth. 18. (a) atoms are very small objects question_answer9) For a given base line, which will show a greater parallax - a distant star or a nearby star? Answer: No, it has dimensions. What is the distance in km of a quasar from which light takes 3.0 billion years to reach us? Nuclear mass density = Mass of nucleus/Volume of nucleus Suggest a distance corresponding to each of the following order of length: (i) \[{{10}^{7}}\mathbf{m}\] (ii) \[\mathbf{1}{{\mathbf{0}}^{\mathbf{4}}}\mathbf{m}\] (Hi) \[{{10}^{2}}\mathbf{m}\] (iv) \[\mathbf{1}{{\mathbf{0}}^{\mathbf{-}}}^{\mathbf{3}}\mathbf{m}\] (v) \[\mathbf{1}{{\mathbf{0}}^{\mathbf{-6}}}\mathbf{m}\] (vi) \[\mathbf{1}{{\mathbf{0}}^{\mathbf{-14}}}\mathbf{m}\]. Converting metric and customary units to solve problems. The density of a cylindrical rod was measured by using the formula ρ=4m/πD2l (b) 7 ✕ 10 … : Length (m), Mass (kg), and time (S) Supplementary & Derived Units 14. Question 2. (e) a proton is much more massive than an electron (c) A vehicle moving with a speed of 18 km h-1 covers ………. CGS System In this system, the unit of length is centimetre, the unit of mass is gram and the unit of time is second. Which of the following readings is the most accurate : (i) \[\mathbf{~5000 m}\] (ii) \[\mathbf{5\times 1}{{\mathbf{0}}^{\mathbf{2}}}\mathbf{m}\] (iii) \[\mathbf{5\times 1}{{\mathbf{0}}^{\mathbf{3}}}\mathbf{m}\]? 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? 9th - University grade ... 9 Questions Show answers. 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. The density of a cube is measured by measuring its mass and the length of its sides. Calculate the diameter of Jupiter. Question 2. Do you think it is possible to increase the accuracy of the screw gauge arbitrarily by increasing the number of divisions on the circular scale? Name two physical quantities having the dimensions \[[M{{L}^{2}}{{T}^{-2}}]\]. 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 Volume of oleic acid in this volume of solution = nV/400 Consider a class room of size 10 m x 8 m x 4 m. Volume of this room is 320 m3. Answer: SONAR stands for ‘sound navigation and ranging’. 1. (ii) Unit system are : NCERT Solutions; Board Paper Solutions; Ask & Answer; School Talk; Login; GET APP; Login Create Account. (i) What values are displayed by Suresh? If 'slap' times speed equals power, what will be the dimensional equation for 'slap'? .•. Distinguish between accuracy and precision. stand for same length? [2010 OL] (i) Which of the following is the unit used to measure mass? [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, Answer: Question 10. Here, v = tan θ 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. What is the basic principle of alpha particle scattering method for estimating the size of the nucleus? S.A. = 4 π r2 question_answer7) Is the measure of an angle dependent upon the unit of length? | Practice Test: Question Set - 01. Mean value, M mean = \(\frac{2.52+2.53+2.51+2.49+2.54}{5}\) False. Dimensions of L.H.S. Suppose we employ a system of units in which the unit of mass equals a kg, the unit of length equals j8 m, the. Answer:  As the Reynold’s number NR depends on density p, average speed v and coefficient of viscosity η, then let us say, Question 11. ft is required to find the volume of a rectangular Mock. (a) 0.007 m2 (b) 2.64 x 104 kg | .•. Q40. Volume of earth = 4/3π R3 Answer: Question 7. Q. Please answer this question urgently..... Share with your friends. The density is accurate only up to three significant figures which is the accuracy of the least accurate factor, namely, the radius of the earth. Do mass and weight have the same dimensions? c. 0.5 m3. Answer:  We know that the usual dimensions of Y are [MLT–2]/[L2] i.e.,[M L-2T-2] It follow that M = FA-1, T = VA~X, L = V2 A-1 (c) CGS system. Briefly explain how you will estimate the molecular diameter of oleic acid. θ=D/d Thickness of hair =3.5 mm/100 = 0.035 mm. The measured values are found to be 1.37 cm, 4.11 cm and 2.56 cm respectively. Justify. = 4 x 3.14 x 2.1 x 2.1 (e) the number of air molecules in your classroom. Measurement of any physical quantity involves comparison with a certain basic arbitrarily chosen and widely accepted reference standard called unit. Question 2. Do all physical quantities have dimensions? The nearest star to our solar system is 4.29 light years away. 19. Question 3. .-. (We are assuming there is no strong wind and that the rain falls vertically for a stationary man). Therefore, time needs more careful measurement. Obtain Dirac’s number, given that the desired number is proportional to mp-1 and me-2. On solving these equations, we find that Unit 1: Physical Quantities, Units and Measurements DRAFT. Answer: Question 5. = 0.5238 x 10-30 m3 He could not understand pound and how it is converted into rupees. Q. Answer: We are given that If \[~x\text{ }=\text{ }a\text{ }+\text{ }bt+c{{t}^{2}},\] where \[x\] is in metre and t in second; then what is the unit of c? Answer:  Volume of one mole of ideal gas, Vg The length, measured by a scale of least count 0.1 cm is 110.0 cm. SI System. question_answer22) Can a quantity have dimensions but still has no units? Suresh again got confused because he never used these units in India. 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.

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