1. 3NA Science (Physics) Chapter 1 Physical Quantities, Units and Measurement

4. Imagine you ask about the age of a person, and the number is a numerical value. The information conveyed during the conversation will not be very specific or useful. How old is your little sister, Jon? She is 12! 12? 12 months? 12 years old?

7. Base Quantities and its Unit m metre length mol mole Amount of substance A ampere current s second time cd candela Luminous intensity K kelvin temperature kg kilogram mass Symbol Base unit Base quantity

8. Very small and very BIG quantities A more efficient way of expressing very big or very small number is to do so in scientific notation, using appropriate prefixes . Bacteria is very small…..it is about 0.000 001 m long… The sun is 149 342 000 000 m away from us…

9. Prefixes

10. How to convert unit?

12. How to convert unit?

15. For accurate length measurement using ruler, the eye should be positioned in line, perpendicular to the point to be read to avoid parallax error . Measuring Length Accurately

17. Main scale Vernier scale 2.1? cm 0.04 cm 2.14 cm Hence a vernier calipers can measure small length accurate to 2 decimal places in cm. How to read write down main scale reading Add vernier scale reading Using Vernier Calipers

18. Qn 1 2.15 cm

19. Qn 2 1.04 cm

20. Qn 3 3.19 cm

22. Micrometer Screw Gauge

23. http://www.upscale.utoronto.ca/PVB/Harrison/Micrometer/Flash/MicSimulation.html

24. How to read write down main scale (sleeve) reading Add thimble scale reading Sleeve scale Thimble scale 4.5? mm 0.12 mm 4.62 mm Hence a micrometer screwgauge can measure small length accurate to 2 decimal places in mm. Using Micrometer Screw Gauge

26. Qn 1 7.32 mm

27. Qn 2 7.63 mm

28. Qn 3 7.00 mm

30. Time Measurement

31. Period of a Simple Pendulum The time taken for a pendulum to complete one oscillation is called the pendulum's period . For the pendulum on the right, one oscillation is from A to B then back to A again.

33. Period of Pendulum Period = 0.35 x 4 = 1.40 s