Title Units & Measurements.pdf ✅

CHAPTER UNITS AND MEASUREMENTS 1 Exercise 1: NCERT Based Topic-wise MCQs 1.1 INTRODUCTION 1. Temperature can be expressed as derived quantity in terms of NCERT Page-17 / N-1 (a) length and mass (b) mass and time (c) length, mass and time (d) None of these 2. Which one of the following is not measured in units of energy? NCERT Page-17 / N-1 (a) Couple × angle (b) Moment of inertia × (angular velocity) 2 (c) Force × distance (d) Impulse × time 1.2 THE INTERNATIONAL SYSTEM OF UNITS 3. Which one of the following pairs of quantities and their units is a proper match? (a) Impulse - N/sec NCERT Appendix A.6.2 and Appendix A.6.3 | Page-213, 214 / N-150, 151 (c) Power - farad (b) Magnetic flux - weber (d) Capacitance - henry 4. One second is defined to be equal to NCERT Page-22 / N-2 (a) 1650763.73 periods of the krypton clock (b) 652189.63 periods of the krypton clock (c) 1650763.73 periods of the cesium clock (d) 9192631770 periods of the cesium clock 5. One yard in SI unit is equal to NCERT Page-209 / N-146 (a) 1.9144 metre (c) 0.09144 kilometre (b) 0.9144 metre (d) 1.0936 kilometre 6. One pico farad is equal to (a) 10−24farad (c) 10−12 farad (b) 10−18farad (d) 10−6 farad 7. 'Torr' is the unit of NCERT Appendix A. 4 | Page-209 / N146 (a) pressure
(b) volume (c) density (d) flux 8. Joule second is a unit of NCERT Appendix A.6.3 | Page-214 (a) energy (b) torque (c) power (d) angular momentum 9. The unit of the coefficient of viscosity in S.I. system is (a) m/kg − s (b) m − s/kg2 (c) kg/m − s 2 (d) kg/m − s 10. The unit of the Stefan-Boltzmann's constant is NCERT Appendix A. 3 | Page-208 / N-145 (a) W/m2K 4 (b) W/m2 (c) W/m2K (d) W/m2K 2 11. The wrong unit conversion among the following is NCERT Page-21 / N-3 (a) 1 angstrom = 10−10m (b) 1 fermi = 10−15m (c) 1 light year = 9.46 × 1015m (d) 1 astronomical unit = 1.496 × 10−11m 12. Unit of specific resistance is NCERT Appendix A 6.3 | Page-214 / N-151 (a) ohm/m2 (b) ohmm3 (c) ohm - m (d) ohm/m 13. Unit of magnetic moment is NCERT Appendix A 6.3 | Page-213 / N-150 (a) ampere-metre 2 (c) weber-metre 2 (b) ampere-metre (d) weber/metre 14. Surface tension of a liquid is 70 dyne/cm. Its value in SI is NCERT Page-17 / N-3 (a) 70N/m (c) 7 × 102N/m (b) 7 × 10−2N/m (d) 7 × 103N/m 15. For the given figure solid angle, dΩ is equal to NCERT Page-17 / N-3
(a) r 2dA steradian (c) r 2 dA steradian (b) dA/r 2 steradian (d) dA/r steradian 16. Which of the following represents incorrect unit? NCERT Appendix A-6.2 | Page-213 / N-150 (a) Pressure = N/m2 (b) Surface tension = N/m (c) Energy = kg − m/sec (d) Stress Strain = N/m2 17. Which of the following is the unit of molar gas constant? NCERT Page-17 / N-3 (a) JK−1mol−1 (b) Joule (c) JK−1 (d) Jmol−1 18. The unit of permeability of free space, μ0 is NCERT Appendix A3 | Page-208 / N-145 (a) (newton-metre) 2 coulomb −2 (b) newton-second 2 / coulomb −2 (c) coulomb newton −1 metre −1 (d) coulomb newton-second −1 19. The numerical values of young's modulus in S.I. unit is β. What is its numerical value in cgs system? (a) β NCERT Page-17 / N-3 (b) 10β ̇ (c) β/10 (d) 100β 20. In the eqn. (P + a V2 ) (V − b) = constant, the unit of a is NCERT Page-17 / N-3 (a) dyne × cm5 (c) dyne /cm3 (b) dyne × cm4 (d) dyne × cm2 21. In equation, r = m2 sin πt, where t represents time. If the unit of m is N, then the unit of r is NCERT Page-17/ N − 3 (a) N (b) N 2 (c) Ns (d) N 2 s 22. If x = at + bt 2 , where x is the distance travelled by the body in kilometers while t is the time in seconds, then the unit of b is NCERT Page-17 / N-3 (a) km/s (b) kms (c) km/s 2 (d) kms2 23. The unit of permittivity of free space, εo is NCERT Appendix A3 | Page-208 / N-145 (a) coulomb 2 /( newton-metre ) 2 (b) coulomb/newton-metre (c) newton-meter 2 / coulomb 2 (d) coulomb 2/ newton-metre 2
24. The electric field is given by E⃗ = A x 3 iˆ + Byjˆ + Cz 2kˆ . The SI units of A, B and C are respectively: [where x, y and z are in m ] NCERT Page-17/N-3 (a) N−m3 C , V/m2 ,N/m2 − C (b) V − m2 ,V/m, N/m2 − C (c) V/m2 , V/m,N − C/m2 (d) V/m,N − m3 /C,N − C/m 25. E, m, J and G denote energy, mass, angular momentum and gravitational constant respectively, then the unit of EJ 2 m5G2 is NCERT Appendix A3, Appendix A.6.2 | Page-208, 213, 214 / N-150, 151 (a) newton (b) metre (c) kilogram (d) second. 26. Velocity (v) and acceleration (a) in two systems of units 1 and 2 are related as v2 = n m2 v1 and a2 = a1 mn respectively. Here m and n are constants. The relations for distance and time in two systems respectively are: (a) n 3 m3 L1 = L2 and n 2 m T1 = T2 NCERT Page-17 / N-3 (b) L1 = n 4 m2 L2 and T1 = n 2 m T2 (c) L1 = n 2 m L2 and T1 = n 4 m2 = T2 (d) n 2 m L1 = L2 and n 4 m2 T1 = T2 27. If unit of length and force are increased 4 times. The unit of energy (a) is increased by 4 times NCERT Page-17 / N-3 (b) is increased by 16 times (c) is increased by 8 times (d) remains unchanged 28. The density of a material in CGS system of units is 4g/cm3 . In a system of units in which unit of length is 10cm and unit of mass is 100g, the value of density of material will be NCERT Page-17 / N-3 (a) 0.4 (b) 40 (c) 400 (d) 0.04 ERRORS IN MEASUREMENTS 29. Systematic errors can be NCERT Page-23 (a) positive only (b) negative only (c) either positive or negative (d) None of these 30. Random error can be eliminated by NCERT Page-23 (a) careful observation (b) eliminating the cause (c) measuring the quantity with more than one instrument (d) taking large number of observations and then their mean 31. The is the error associated with the resolution of the instrument. NCERT Page-24 (a) parallax error (c) random error