Title 2. Units and Measurements.pdf ✅

EduHulk 696 PHYSICS PHYSICS EBD_7418
EduHulk UNITS AND MEASUREMENTS 96 PHYSICS7
8 PHYSICS Topic 1: Unit of Physical Quantities 1. Which one of the following pairs of quantities and their units is a proper match? (a) Impulse – N/sec (b) Magnetic flux – weber (c) Power – farad (d) Capacitance – henry 2. One second is defined to be equal to (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 3. One yard in SI unit is equal to (a) 1.9144 metre (b) 0.9144 metre (c) 0.09144 kilometre (d) 1.0936 kilometre 4. One pico farad is equal to (a) 10–24 farad (b) 10–18 farad (c) 10–12 farad (d) 10–6 farad 5. ‘Torr’ is the unit of (a) pressure (b) volume (c) density (d) flux 6. Very large distances such as the distance of a Planet or a star from Earth can be measured by (a) Spectrograph (b) Millikan’s oil drop method (c) Parallax method (d) All of these 7. Joule second is a unit of (a) energy (b) torque (c) power (d) angular momentum 8. Temperature can be expressed as derived quantity in terms of (a) length and mass (b) mass and time (c) length, mass and time (d) None of these 9. One unified atomic mass unit is equal to (a) 12 times the mass of one carbon-12 atom (b) 1 12 of the mass of 12 atoms of C-12 (c) 1 12 of the mass of one atom of C-12 (d) 12 times the mass of 12 atoms of C-12 10. Match the columns I and II Column I Column II (A) Practical unit (1) radian (B) Base unit (2) light year (C) Derived unit (3) kg-ms–1 (D) Complementary unit (4) second (a) (A)®(4); (B)®(2); C®(1); (D)®(3) (b) (A)®(2); (B)®(4); C®(3); (D)®(1) (c) (A)®(3); (B)®(2); C®(4); (D)®(1) (d) (A)®(2); (B)®(4); C®(1); (D)®(3) 11. Light year is (a) light emitted by the sun in one year. (b) time taken by light to travel from sun to earth. (c) the distance travelled by light in free space in one year. (d) time taken by earth to go once around the sun. 12. The unit of the coefficient of viscosity in S.I. system is (a) m/kg-s (b) m-s/kg2 (c) kg/m-s2 (d) kg/m-s 13. The unit of the Stefan-Boltzmann's constant is (a) W/m2K4 (b) W/m2 (c) W/m2K (d) W/m2K2 14. The wrong unit conversion among the following is (a) 1 angstrom = 10–10m (b) 1 fermi = 10–15m (c) 1 light year = 9.46 × l015m (d) 1 astronomical unit = 1.496 × 10–11m 15. Unit of specific resistance is (a) ohm/m2 (b) ohm m3 (c) ohm – m (d) ohm/m 16. Unit of magnetic moment is (a) ampere–metre2 (b) ampere–metre (c) weber–metre2 (d) weber/metre 17. Surface tension of a liquid is 70 dyne/cm. Its value in SI is (a) 70 N/m (b) 7 × 10–2 N/m (c) 7 × 102 N/m (d) 7 × 103 N/m 18. Assertion : When we change the unit of measurement of a quantity, its numerical value changes. Reason : Smaller the unit of measurement smaller is its numerical value. (a) Assertion is correct, reason is correct; reason is a correct explanation for assertion. (b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion (c) Assertion is correct, reason is incorrect (d) Assertion is incorrect, reason is correct. 19. For the given figure solid angle, dW is equal to dW dA r (a) r2dA steradian (b) dA/r2 steradian (c) 2 r dA steradian (d) dA/r steradian 20. Column I Column II (A) Distance between earth & stars (1) micron (B) Inter-atomic distance in a solid (2) angstrom (C) Size of the nucleus (3) light year (D) Wavelength of infrared laser (4) fermi (5) kilometre (a) (A)®(1); (B)®(3); C®(4); (D)®(2) (b) (A)®(3); (B)®(2); C®(4); (D)®(1) (c) (A)®(5); (B)®(2); C®(3); (D)®(1) (d) (A)®(2); (B)®(4); C®(1); (D)®(3) Exercise 1 : Topic-wise MCQs EduHulk 96 PHYSICS EBD_7418